Chennai is unforgiving on clothing. Heat, humidity and dust will expose a bad fabric choice within an hour. This is a practical ranking of what actually works here, based on what customers come back for rather than on what the swing tags claim.
What works best here
Voile and fine lightweight cottons — the most breathable option available. Slightly sheer, so best in white and light colours over a vest. Unbeatable in April and May.
Poplin — the everyday workhorse. A smooth, tight plain weave that presses crisply and breathes well. The default formal shirt fabric, and rightly so.
Linen and linen-cotton blends — outstanding for airflow. Pure linen creases, which is either its charm or its problem depending on your temperament; the blend creases far less and keeps most of the comfort.
What works, conditionally
Twill — a diagonal weave with more body and a soft sheen. Drapes beautifully and resists wrinkles better than poplin, but it is warmer. Good for air-conditioned offices, less so for a day spent outdoors.
Oxford — a heavier basketweave, durable and casual. Fine for a button-down worn on a cooler evening; too heavy for daily formal wear here.
Wrinkle-resistant finishes — genuinely useful in this city if you commute in the heat, though the treatment slightly reduces breathability. A fair trade for many people.
What to avoid
High-polyester blends. They are cheap, they hold their press, and they will make you miserable — they trap heat, they do not absorb moisture, and sweat marks show and linger. A small percentage of synthetic for wrinkle resistance is fine; a shirt that is majority polyester is not worth owning in this climate at any price.
Also treat heavy satin and rayon shirts with caution. They photograph well and read premium, but they trap warmth and are unpleasant by mid-morning.
Making shirts last in this climate
Wash cool and dry in shade — direct Chennai sun will fade colours within a season. Rest a shirt for a day between wears so the fibres recover; shirts worn back-to-back wear out markedly faster.
Store on proper hangers with the top button fastened so the collar keeps its shape. And press collar and cuffs from the inside out, which prevents the shine that develops on the outer surface over time.