Best Baby Carrier Buying Guide: Safety, Types, and Indian Picks

• Two safety rules govern all babywearing: TICKS (Tight, In view, Close enough to kiss, Keep chin off chest, Supported back) for the airway, and hip-healthy M-shape positioning (knees higher than bottom, thighs supported knee-to-knee).
• Avoid narrow-seat carriers that leave the legs dangling straight down, especially in babies under 6 months, the International Hip Dysplasia Institute warns this can stress the developing hip joint.
• Pick the carrier type for your stage: a stretchy wrap or newborn-ready structured carrier for the early weeks, a ring sling for quick on-and-off, a soft structured carrier or woven wrap for longer outings.
• For India's climate, choose breathable cotton, linen, or mesh, take cooling breaks in summer, and dress your baby one layer less than you are wearing.
• Never wear a baby on a two-wheeler, while cooking over flame, or for unattended sleep; a carrier is not a substitute for a car seat.
• A mid-tier carrier (around INR 2,500 to 4,500) or a pre-loved premium one is far better value than several cheap carriers that end up unused.

Carrying your baby in a sling or carrier, kept close against your body, is one of the oldest infant-care practices in the world and one of the best supported by evidence. The benefits reach both baby and parent, and the practice fits naturally into Indian family life, whether you are in a busy city flat or a village home.

Less crying. A well-known randomised study (Hunziker and Barr, Pediatrics, 1986) found that babies carried for about three extra hours a day cried roughly 43 percent less overall and around 51 percent less during the peak evening colic hours. The likely reasons are continuous contact, gentle motion, your heartbeat and breathing, the upright position, and sensory input that echoes life in the womb. If evening fussiness is your main struggle, see our guides to the evening witching hour and soothing a colicky baby.

Healthy hips and spine. A properly fitted ergonomic carrier holds the hips in a natural M-shape, knees higher than the bottom, weight on the thighs rather than the crotch. This is the position the International Hip Dysplasia Institute (IHDI) recommends, and it is exactly how traditional Indian saree and dhoti carries cradle a baby. The spine stays in its natural gentle C-curve, supported by your body.

Easier breastfeeding. Frequent carrying supports milk supply and makes it easy to read and respond to feeding cues. The skill of nursing while wearing takes practice but is hugely useful for busy days; start with our breastfeeding positions basics, and if supply is a worry, see low milk supply.

Calmer reflux and better sleep. The upright position lets gravity work against spit-up after feeds, which is one reason carriers feature in positional advice for infant reflux. Many babies also nap longer and more peacefully when worn.

More language and connection. A worn baby is at adult eye level, soaking up faces, speech, and social cues, which supports language and emotional development and strengthens secure attachment.

Hands free for the parent. You can cook, work, mind an older child, or run errands while still giving your baby the closeness they need, valuable in nuclear-family homes where help is limited.

A role for fathers and grandparents. A carrier is gender-neutral equipment. It lets Fathers & Postpartum Care: Partnering in Healing & Bonding, grandparents, and other family members share comforting care, supporting bonding and giving the mother real breaks.

Support for recovery. The close contact helps the oxytocin and prolactin release that aids uterine recovery and mood; babywearing is one practical tool among many that can ease the early postpartum weeks.

The bottom line: a good carrier (around INR 1,500 to 5,000) earns its cost in months of daily use, calmer babies, and easier outings. The question is not whether to babywear, but which carrier to choose.

Two safety frameworks govern modern babywearing: the TICKS rule for airway and positioning, and the IHDI guidance for hip-healthy positioning. Learn both before you wear your baby.

TICKS stands for:

• Tight — the carrier holds the baby snug against you, with no slack that lets them slump. Loose carriers cause most airway incidents.
• In view at all times — the baby's face is visible, never covered by fabric or turned in against your chest with the nose blocked.
• Close enough to kiss — the baby's head is high enough that you can tip your chin and kiss the forehead.
• Keep chin off chest — the chin must not press down onto the chest, which can block a baby's tiny airway. Keep a finger-width gap.
• Supported back — the back is supported in its natural curve, with fabric covering it from bottom to neck (or upper back for older babies).

Carriers fall into a few categories, each with its own strengths and best use. (Prices below are approximate, in INR.)

Stretchy wraps. A long stretchy fabric (about 4.5 to 5.5 m, soft cotton-spandex) tied around you and the baby. Best for newborns up to roughly 6 to 9 kg or 4 to 6 months. The cradling feel suits tiny babies and spreads weight well. Limitations: they sag with heavier babies and feel warm in Indian summers. Indian options: Anmol Boba Wrap (1,500 to 2,500), Soulslings Stretchy Wrap (2,000 to 3,500), generic wraps on Amazon India (800 to 1,500). Imported: Solly, Moby, Boba Wrap (roughly 3,000 to 5,500).

Woven wraps. A long non-stretch woven fabric (cotton, linen, hemp, or blends). The most versatile type and the only one that supports a baby from newborn through toddler with the same piece of cloth. The learning curve is steeper, allow 1 to 2 weeks of practice with a doll first. Indian: Soulslings (3,500 to 8,000), Anmol (3,000 to 6,000). Imported: Didymos, Girasol, Storchenwiege (6,000 to 15,000).

Ring slings. A fabric (about 2 m) with two rings forming an adjustable pouch over one shoulder. Great for newborns through toddlers in front or hip carry, quick to use, and excellent for nursing. The one-shoulder design is fine for shorter wears. Indian: Soulslings (2,000 to 4,500, Oeko-Tex certified), Anmol (1,800 to 3,500). Imported: Sakura Bloom, Maya Wrap.

Soft structured carriers (SSCs). A buckle-and-strap carrier with a panel, waist belt, and shoulder straps, what most people picture as a baby carrier. Quick to put on, needs no wrapping skill, easy for partners and grandparents, and distributes weight across hips and shoulders. Many are newborn-ready with an insert or built-in setting. Indian: Anmol SSC (2,500 to 4,500, designed for Indian climate and sizing), R for Rabbit Upsy Daisy 4-in-1 (2,500 to 4,500), Chinmay Kids (3,000 to 5,500), LuvLap and Mee Mee 4-in-1 (budget). Imported: Ergobaby Omni 360 (8,000 to 14,000), Ergobaby Embrace (5,000 to 8,000), LilleBaby Complete (8,000 to 13,000), BabyBjorn Mini and Move, Tula Free-to-Grow, Manduca.

Mei tais (meh dais). A panel with four long fabric straps tied at waist and shoulders, a hybrid of wrap and SSC. Faster than a wrap, no buckles to break. Indian: Soulslings (3,500 to 6,000), Anmol (3,000 to 5,000).

Pouch slings. A fixed-size fabric tube over one shoulder, sized to one person and with some safety concerns in older designs. Generally not recommended; choose a ring sling instead.

Onbuhimo. Like a mei tai but with no waist belt, useful for back-carrying older babies or for pregnant parents.

Hip seats. A shelf worn on the waist, sometimes with an attached panel. Limited use; can strain the back. Available in India (R for Rabbit, others, 2,000 to 4,000).

The best first carrier for most Indian families is either a stretchy wrap for the early weeks (if you can commit to a short learning curve) or a newborn-ready SSC for everyday ease. Many families end up with two: a wrap or ring sling for quick use, and an SSC for longer, shared outings.

India's weather ranges from humid coastal heat to dry desert summers, harsh northern winters, and the monsoon. Fabric and design make a real difference to comfort.

Hot and humid (Mumbai, Chennai, Kolkata, Kochi, coastal areas). Prioritise breathability. Choose 100 percent cotton, lightweight cotton-linen, or mesh panels; avoid heavy cotton-spandex, fleece, or thick padding. The BabyBjorn Move and LilleBaby Complete All Seasons (both with mesh) suit hot weather, as do Soulslings cotton and linen wraps. Take a carrier break every hour or two to let heat escape, and check the baby for heat rash on the back and behind the knees.

Hot and dry (Delhi, Rajasthan, western India in summer). Similar fabric advice; dry heat is a little easier to tolerate but hydration matters more, breast milk on demand for younger babies, water sips after 6 months.

Mild (Bengaluru, hill regions, Pune most of the year). The easiest babywearing weather; most carriers and fabrics work well.

Cold (Delhi winter, Punjab, Himachal, Uttarakhand, Kashmir). Prioritise warmth with wool blends, thicker cotton, or padded panels. Remember your body heat plus the carrier adds warmth, so dress the baby one layer less than you are wearing and cover the head with a soft cap. A shawl over the whole pair adds warmth outdoors, but never let it cover the baby's face. Remove outer layers when you go into heated rooms.

Monsoon (June to September). Keep both of you reasonably dry. A babywearing rain cover (Soulslings and similar, 1,500 to 2,500) helps for short exposure; for heavy rain, stay indoors. Quick-dry fabrics recover faster from humidity.

Fabric notes. 100 percent cotton is the workhorse: breathable, washable, durable. Linen is slightly cooler and supportive. Hemp is very durable but stiff at first. Bamboo is soft and breathable but less hardy. Wool is excellent for winter only. Synthetics like polyester fleece and nylon are not recommended against the baby's skin in heat.

Care and skin. Most fabric carriers machine-wash in cool water and air-dry; wool needs a wool-safe wash. Wash before first use. In humid weather, a soft cotton singlet between baby and fabric reduces direct skin contact; if heat rash appears, remove the carrier, cool and dry the skin, and switch to a lighter fabric.

Climate-suited Indian brands: Soulslings (Oeko-Tex certified, designed for Indian climate and sizing), Anmol Baby Carriers, Chinmay Kids (hot-humid focus), and R for Rabbit (mid-tier). Imported hot-weather options include LilleBaby All Seasons, BabyBjorn Move, and the Ergobaby Omni 360 Cool Air Mesh.

The right carrier depends on your baby's age and development.

Newborn (0 to 6 weeks). Tiny (about 3 to 4.5 kg) with limited head control, the baby needs full head and neck support. Stretchy wraps suit this stage well; structured carriers with a newborn setting or insert (Ergobaby Omni 360, LilleBaby Complete, Ergobaby Embrace, BabyBjorn Mini) also work from birth. Practise with a soft toy for a few days first. Ring slings work from birth but need a little more confidence with airway positioning. This is also the prime window for skin-to-skin contact.

Young infant (6 weeks to 4 months). Weight 4 to 7 kg, head control improving. All newborn options continue. Keep the baby facing you, FFO is not yet appropriate.

Older infant (4 to 6 months). Head and trunk control develop; weight 6 to 8 kg. Stretchy wraps may start to sag, so many families move to woven wraps, ring slings, or SSCs. FFO becomes possible from 5 to 6 months in carriers designed for it, and hip carry becomes appropriate. Back carry can begin around 6 months with help.

Older baby (6 to 12 months). Increasingly active and wriggly; quick on-and-off carrying becomes valuable. Ring slings shine for quick hip carries, SSCs for longer outings, and back carry in an SSC or woven wrap for walks and travel. Weight reaches 8 to 11 kg, so parent comfort matters more.

Toddler (12 to 24 months). Walking but still wanting to be carried when tired or in crowds. Toddler-sized carriers (LilleBaby Carryon, Ergobaby toddler range, Tula Toddler) and woven wraps suit best, and a back carry is ideal for sightseeing and long outings.

Older toddler and preschooler (24 to 48 months). The carrier comes out less often but still helps for tired or unwell moments. Toddler-sized SSCs and woven wraps work; most families gradually phase out babywearing here.

Twins and close-in-age siblings. Twin carriers exist (TwinGo, Weego) but are heavy; many parents instead wear one baby each, or one in front and one on the back. See breastfeeding twins for feeding logistics.

Preemies and low-birth-weight babies. Kangaroo mother care (skin-to-skin chest carry) is the gold standard, supported by WHO, the Indian Academy of Pediatrics, and Indian NICU guidelines. Standard stretchy wraps and ring slings also work after discharge; the usual safety principles (TICKS, hip-healthy, alert parent) all apply. Discuss individual guidance with your NICU team and pediatrician.

Carriers in India range from under INR 1,000 to over 15,000. Here is honest guidance by tier.

Under INR 1,000. Mostly basic Mee Mee or LuvLap front carriers with narrow seats that are not hip-healthy and have little adjustability. Use only briefly with older babies (over 4 months, good head control), facing you. Better to save for the next tier.

INR 1,000 to 2,000. Budget 4-in-1 carriers (LuvLap, Mee Mee, generic). Multiple positions but basic build and usually a narrow seat. Acceptable for short, occasional use, not a daily driver. Prefer LuvLap Galaxy or Mee Mee 4-in-1 over the cheapest options.

INR 2,000 to 4,000. The sweet spot for many families. Anmol Standard SSC (2,500 to 3,500, India-designed, breathable, hip-healthy seat), R for Rabbit Upsy Daisy 4-in-1, Chinmay Kids SSC, Anmol Ring Slings, and basic Soulslings Stretchy Wrap. Here you get genuine hip-healthy positioning, reasonable comfort, and durable construction.

INR 4,000 to 8,000. Premium Indian and entry-level imports: Anmol Premium SSC with mesh, Soulslings premium ring slings, wraps, and mei tais, Chinmay Kids premium, Ergobaby Embrace (excellent for newborns), and BabyBjorn Mini. High-quality fabrics, refined design, and often Oeko-Tex certification (Soulslings).

INR 8,000 to 14,000. Premium imports and high-end Indian: Ergobaby Omni 360 (one of the most-recommended SSCs worldwide, newborn to toddler, hip-healthy in all positions), Omni 360 Cool Air Mesh, LilleBaby Complete All Seasons, BabyBjorn Move, Tula Free-to-Grow, Manduca, and premium Soulslings or Anmol woven wraps. The gold standard for daily use.

Above INR 14,000. Specialty imported woven wraps (Didymos, Girasol, Storchenwiege) and silk ring slings (Sakura Bloom). For committed babywearers; the functional gain over the previous tier is modest.

Pre-loved carriers. India's babywearing community trades extensively, with premium carriers at 40 to 60 percent of new price through Facebook groups, WhatsApp groups, and OLX or Quikr. A pre-loved Ergobaby Omni 360 at INR 5,000 is excellent value. Check for broken buckles, torn fabric, or weak stitching, wash before first use, and buy from community members to avoid counterfeits.

Rentals and libraries. Some cities have babywearing libraries or rentals to try styles before buying; check Babywearing International chapters and local groups.

Free or low-cost. A 3 to 5 m length of breathable, woven (not stretchy) cotton, at least 60 cm wide, from any fabric shop (INR 200 to 500) works as a basic wrap, much as traditional Indian babywearing always has. Free YouTube tutorials in Hindi, English, and regional languages teach the front wrap cross carry.

Honest recommendation: if budget allows, an Anmol SSC or Soulslings ring sling in the INR 2,500 to 4,000 tier, or an Ergobaby Omni 360 or LilleBaby Complete in the INR 8,000 to 13,000 tier, offers the best value-to-quality balance for most Indian families.

Buying a good carrier is half the job; using it correctly is the other half.

Before the first use. Read the manual and watch your carrier's tutorial video (Anmol, Soulslings, Ergobaby, LilleBaby, and others post these, often in Hindi too). Practise with a soft toy for 15 to 30 minutes a day for a few days, and have someone watch you the first time you wear your baby.

Adjust before you put the baby on. For SSCs, set the waist belt (at the natural waist for newborns, lower toward the hips as the baby grows), adjust shoulder straps, and set seat width to the baby's size. For wraps, pre-tie if using a pocket wrap cross carry. For ring slings, thread the rings and arrange the fabric over your shoulder.

Putting the baby on. With an SSC, hold the baby to your chest, fasten the waist belt first, then the shoulder straps, then check positioning. With a stretchy wrap, insert one leg at a time into the pouch, then arrange the cross straps. With a ring sling, position the baby vertically, guide the legs into the M-shape, and spread the fabric knee-pit to knee-pit.

Check immediately: run the TICKS check, then the hip check (knees higher than bottom, M-shape, fabric supporting thigh to thigh).

Comfort. A well-fitted carrier is comfortable for both of you. Shoulder or back pain within 10 minutes usually means the carrier is too loose or straps need rebalancing. The baby high on your chest (forehead near your chin) is more comfortable than low on your belly.

Solo wearing. For SSCs, put the carrier on yourself first, then bring the baby in and fasten the second strap. For wraps, pre-tie then insert. For ring slings, position over the shoulder first.

Removing. Do it over a soft surface, loosen fully before lifting the baby out, and support the head and body.

Nursing in the carrier (takes practice). Loosen the carrier to lower the baby to breast level, achieve a deep latch, and keep a hand on the baby's back. Crucially, tighten back to the upright position after the feed, never carry in the loose nursing position because of airway and hip concerns.

Back carry. Practise over a soft surface and ask for help the first several times. Keep the baby high on your back (head near your neck) and use a mirror to check positioning until confident.

Common fixes: baby too low (tighten or reposition), straps too loose (snug them fully), one strap looser than the other (even them out to avoid back pain), legs hanging straight (widen the seat or change carriers).

Most parents find a new carrier feels second nature within 5 to 10 uses. Persistent difficulty usually means the wrong carrier for your body, or a fixable technique issue, seek help from an experienced babywearer, a Babywearing International chapter, or La Leche League India.

Most babywearing problems come from a handful of recurring mistakes.

1. A narrow-seat carrier as your daily carrier. Narrow seats leave the legs dangling straight down rather than in the M-shape, which the IHDI links to hip dysplasia with prolonged use in young infants. Choose an adjustable wide seat that supports knee-pit to knee-pit.

2. Forward-facing-out too early. Wait for 5 to 6 months and full head and trunk control, use a carrier designed for FFO, and limit sessions to 30 minutes.

3. Not checking the airway. A baby's airway is easily blocked by a chin-to-chest position or fabric over the face, most critical before 4 months. Do a TICKS check every few minutes early on and whenever the baby falls asleep, keeping a finger-width gap at the chin.

4. Bending at the waist. This pitches the baby forward. Squat instead, with a hand on the baby's bottom.

5. Risky activities. No cooking over flame, hot drinks, power tools, cycling, or swimming (outside a specialised water carrier) while wearing a baby.

6. Carrying on a two-wheeler. Common in India and extremely dangerous, in even a low-speed crash the baby can be ejected or crushed. No carrier makes this safe. Use a car or auto-rickshaw; this is a non-negotiable boundary.

7. A carrier as an unattended sleep space. A baby asleep on an awake, alert parent is safe; on a sleeping or absent parent it is not. Transfer a sleeping baby to a flat, firm surface, and never nap with the baby still in the carrier.

8. Ignoring discomfort. Persistent shoulder, Postpartum Back Pain: Causes, Recovery & Physiotherapy in India, hip, or neck pain signals a fit problem. Adjust, or get help, rather than pushing through.

9. Not adjusting as the baby grows. Every 2 to 3 months, recheck seat width, panel height, strap length, and belt position.

10. Buying several cheap carriers instead of one good one. Five INR 1,500 carriers cost more, and disappoint more, than one well-chosen INR 4,000 carrier used for two years. The pre-loved market makes premium carriers affordable.

11. Forgetting partner fit. If a partner will use it too, both bodies need to fit. Wraps and ring slings adjust most easily across sizes.

12. Defaulting to the stroller for everything. Carriers win in crowded markets, on stairs and escalators, in autos, and for calming a fussy baby, situations common in Indian cities where pavements are uneven and lanes are narrow. Use both as the moment suggests.

Indian-specific notes. Summer temperatures above 40 degrees need shorter sessions, breaks, hydration, and monitoring for heat illness in both of you. In crowds, keep the baby facing inward for protection. On stairs, keep a hand on the railing and do not also carry shopping.

Where to get help. IBCLC lactation consultations (INR 1,500 to 4,000) can cover carrier questions alongside feeding; Babywearing International chapters and La Leche League India offer in-person help; and the IHDI and KellyMom websites have free resources.

One of the highest-value uses of a carrier is nursing while wearing. The skill takes practice but transforms daily life, especially with an older child to mind, working from home, or an active outdoor routine.

Why it helps. Hands-free, discreet feeding; reliable comfort in busy places; easy on-cue feeding in the early weeks, which supports supply and helps prevent mastitis and blocked ducts through frequent emptying; and easier continued breastfeeding for working mothers.

Best carrier types for nursing. Ring slings are excellent (the shoulder fabric easily lowers the baby to breast level); stretchy wraps work well in the early weeks; woven wraps have dedicated nursing carries; and SSCs work with practice (loosen the straps to lower the baby). Some SSCs (Ergobaby Omni 360, LilleBaby Complete) have a nursing setting.

Technique (general). Start in the standard upright carry, loosen the carrier so the baby's mouth reaches breast level, bring the baby into a deep latch, and keep a hand on the back during the feed. After the feed, tighten back to the upright position and recheck TICKS and the hip position.

Critical safety reminder. Never leave the baby in the lowered nursing position after the feed, the airway can be compromised and the hips are not optimally supported. Always return to the standard upright carry.

Building confidence. Early attempts feel awkward and the latch may be imperfect; try at least 5 to 10 times. The reward is a single skill that adds enormous flexibility.

Public nursing in India. Many Indian mothers feel pressure to avoid feeding in public. A carrier solves this, the fabric covers most of the chest, so the baby can feed at weddings, on transport, or in restaurants with little or no visible exposure, and a separate nursing cover is rarely needed.

Nursing an older sibling. With the new baby worn in a carrier, a toddler can be nursed from the breast, making tandem nursing more manageable.

Pumping while wearing. Wearable pumps (Elvie, Willow, Imani) can run inside clothing while the baby is carried, useful for working mothers.

Carrier and supply. Close contact triggers oxytocin and prolactin, and frequent feeding maintains supply better than scheduled feeds; if supply is a concern, increasing babywearing time can be one helpful step alongside other supply-supporting strategies.

When carrier nursing is not the first choice. In the first 6 weeks while the latch is still being established, or with significant latch pain or positioning needs, focus on sit-down nursing first and add the carrier once feeding is well established (often 4 to 8 weeks). For demonstrations, La Leche League meetings, Babywearing International chapters, and IBCLC consultations can help with both the latch and the carrier together.

A carrier is heavily used equipment that lasts longer and works better with simple care.

Cleaning. Most fabric carriers (wraps, ring slings, mei tais, SSCs) machine-wash in cool water, check your manual. Wash before first use, after any spit-up, leak, or heavy sweat, and periodically for hygiene. Use a mild, fragrance-free detergent, skip fabric softener, and air-dry where possible. Stretchy wraps may shrink slightly on the first wash, then stretch back. Wool needs a wool-safe wash (cold water, careful flat drying). For SSCs, fasten buckles during the wash; some premium carriers with leather elements need spot cleaning only. Between washes, spot-clean stains with a damp cloth and mild soap.

Hot-weather care. Daily-used carriers in humid climates need more frequent washing; quick air-drying in the sun helps, bring it in before evening dew.

Safety inspection. Every 1 to 2 weeks, check stitching at stress points (waist and shoulder junctions, buckle attachments, seat), buckles (cracks or failure to lock), straps (tears or fraying), fabric (thin spots or holes), and ring-sling rings (cracks, sharp edges).

When to retire a carrier. Broken buckles, torn load-bearing fabric, deformed rings, or compromised stitching; the baby past the maximum weight; lost comfort from wear; or a manufacturer recall (check the brand's site periodically). Premium carriers often last several years and multiple babies; budget ones may need replacing within 1 to 2 years.

Storage. Keep it clean and dry to prevent mould, out of direct sun, and within easy reach, a hook near the door makes daily use far more likely. Fold into a clean bag for travel.

Multiple carriers and sharing. Many families rotate 2 to 3 carriers (a ring sling for quick use, an SSC for outings, perhaps a woven wrap), which spreads the wear. Most modern carriers adjust across a wide size range so both parents and grandparents can share one.

Pre-loved resale. When you are done, a carrier usually has plenty of life left, resell through babywearing Facebook groups, OLX, Quikr, or parent networks. Wash thoroughly and include the instructions if you have them.

Growing with your baby. Standard carriers work from newborn to about 12 to 18 months, toddler sizes to 36 months or beyond. Adjust seat width, panel height, strap length, and belt position as the baby grows, the settings that suited a 3-month-old will not suit a 15-month-old.

Indoor use. Carriers help indoors too, calming a fussy baby or freeing your hands, often a large share of total use in the early months. Pair carrying with floor play and tummy time so your baby also gets time to move and develop.

Final advice: the carrier you actually use beats the one in the cupboard. Choose one that fits your body, your baby, your lifestyle, and your budget; use it often; care for it; and replace it when it wears out.

• International Hip Dysplasia Institute — Baby Carriers, Seats & Other Equipment
• Hunziker UA, Barr RG. Increased carrying reduces infant crying: a randomized controlled trial. Pediatrics. 1986
• World Health Organization — Kangaroo mother care: a transformative innovation in health care
• Indian Academy of Pediatrics (IAP) — Kangaroo Mother Care guidelines
• NHS — Soothing a crying baby