GSM — grams per square metre — is the single most useful number on a shirt tag you'll probably never see. Most Indian brands won't print it. Most Western brands won't either. But if you understand it, you can predict almost exactly how a shirt will feel on your skin at 38°C without ever touching the fabric.
What it actually measures
GSM is the weight of one square metre of the fabric. It's a proxy for density, and density controls two things that matter for Indian climates: how much air the fabric lets through, and how much heat it traps. Lower GSM = lighter, more breathable. Higher GSM = heavier, warmer, more structured.
The Velaro GSM ladder
- 140–160 GSM — Light, breezy, hot-weather weight. Linen blends and loosely-woven cottons live here. Best for sustained heat above 36°C.
- 160–200 GSM — Everyday office-to-street weight. Cotton twills and oxford weaves. The zone most Velaro essentials target.
- 200+ GSM — Insulating, cool-climate weight. Flannels, heavy cottons. Not what you want in Chennai April.
Why brands hide it
Because most shirts on the Indian market are 220+ GSM — fabric leftover from Western cold-climate markets, re-sold without reformulating for Indian heat. Printing GSM would expose that. Velaro prints it on every tag because the number tells the truth and the number is the point.