A Plain-English Fabric Guide: Cotton, Linen, Polyester and Blends

Almost every disappointing purchase is a fabric problem in disguise. The shirt that looked crisp online and turned translucent in daylight, the kurti that lost its shape after three washes, the jacket that trapped sweat instead of warmth — none of those are styling failures. They are the composition label doing exactly what it said it would do, to a buyer who never read it.

The good news is that the label is short. Most garments are made from four or five fibres in various proportions, and once you know how each behaves, you can predict how a piece will wear before you own it. Here is the whole vocabulary, in plain English.

Cotton

Cotton is a natural plant fibre, and it is the default for good reason: it is breathable, it takes dye well, it gets softer with washing, and it does not hold odour the way synthetics do. In a hot, humid climate it is hard to beat for anything worn next to the skin.

Its weaknesses are equally predictable. Pure cotton creases, it shrinks on the first hot wash, it dries slowly, and it loses shape at the knees and elbows over a long day. None of that is a defect. It is the trade you make for comfort.

What to look for on a cotton label

Combed cotton — the short fibres have been removed, so the fabric is smoother and pills less. Worth the small premium on tees.
Long-staple or extra-long-staple (often sold as Pima, Supima or Egyptian) — longer fibres mean a stronger, softer, longer-lasting cloth.
GSM, on knitwear and tees. Roughly 140–160 GSM is a light summer tee; 180–200 GSM is a substantial everyday tee that will not go see-through.
Pre-shrunk or garment-washed — the shrinking has already been done, so the size you buy is the size you keep.

Linen

Linen is made from flax, and it is the most breathable fabric in common use. It moves moisture away from the skin faster than cotton and dries faster too, which is why it has been the hot-weather fabric of choice for several thousand years. It is also genuinely durable — linen gets stronger when wet, and a good linen shirt outlives a cotton one.

It creases. It creases immediately, visibly, and permanently until you wash it again. If that will bother you, buy a linen-cotton blend instead of pure linen; you keep most of the breathability and lose most of the crumple. If it will not bother you, pure linen in high summer is a genuine comfort upgrade and the creasing reads as intentional.

Polyester and other synthetics

Polyester is a plastic fibre, and it is very good at several specific jobs: holding a colour, resisting creases, keeping a shape, drying fast, and costing little. That combination is why it dominates the low end of the market and also why technical outerwear is full of it.

The problem is breathability. Polyester does not absorb moisture — it moves it along the surface, which works well when air is flowing and works badly when it is not. In still, humid heat a 100% polyester shirt traps sweat against the skin and holds odour afterwards, because the bacteria that cause odour thrive on the residue synthetics leave behind.

So the rule is not "avoid polyester". It is: avoid polyester next to the skin in heat, and welcome it in a jacket shell, a rain layer, or anywhere you need structure and weather resistance.

The synthetics you'll meet in outerwear

Nylon (polyamide) — stronger and more abrasion-resistant than polyester, common in shells and bags.
Elastane / spandex / Lycra — all the same fibre under different names. At 2–5% it gives stretch and recovery; above that a garment starts to feel clingy and loses its shape sooner.
Fleece — usually polyester, brushed to trap air. Warm and light, but almost useless against wind on its own.
Polyester fill (often branded as a synthetic down alternative) — insulates when damp, unlike real down, and costs far less.

Viscose, rayon and modal

These are semi-synthetics: natural cellulose that has been chemically processed into fibre. They drape beautifully, feel cool and smooth, and are why so many flowing kurtis and dresses hang the way they do. Modal and Tencel/lyocell are the better-behaved members of the family — softer, stronger, and more stable in the wash.

The catch is that viscose is weak when wet. A viscose garment thrown into a hot machine wash can shrink, stretch out of shape, or both. Wash cool, wash gently, and dry flat, and it will last; treat it like cotton and it will not.

Wool

Wool insulates even when damp, resists odour better than any other common fibre, and regulates temperature rather than simply trapping heat. Merino is the fine-fibred version that does not itch and can be worn against the skin. It is expensive, and in most Indian winters a wool blend or a good synthetic-fill jacket does the job for a fraction of the price — but for a sweater you will wear for a decade, wool is the one that survives.

How to read a blend

Blends exist to borrow a property from one fibre and lend a property to another, and the percentages tell you which direction the borrowing goes. The fibre listed first dominates the character of the cloth.

60% cotton / 40% polyester — a workhorse. Creases less than cotton, breathes more than polyester. The standard for everyday shirts and hoodies.
55% linen / 45% cotton — most of linen's coolness, much less of its crumple. The best summer-shirt blend for most people.
95% cotton / 5% elastane — cotton comfort with enough stretch to move in and enough recovery to keep its shape. Ideal for fitted tees and slim trousers.
Anything with over 20% viscose — expect lovely drape and a demanding wash routine.
100% polyester on a shirt at a very low price — usually a sign the cost has been taken out of the fabric. Check the GSM before you buy.

A two-minute decision process

Before you buy anything, ask what the garment has to do, then check the label against it. Next to the skin, in heat: cotton, linen, or a blend led by one of them. Structure that must survive a full day: cotton with a little elastane, or a cotton-polyester blend. Wind, rain or cold: synthetics, deliberately. Something you want to still own in five years: natural fibres in a high-quality weave, and a willingness to wash them properly.

That is the whole system. It takes ten seconds at the point of purchase and it eliminates most of the ways a garment can disappoint you.