XXXL — 3XL — is a 46 in Indian menswear, not the 44 it is often taken for. XXXXL, written 4XL, is usually drafted for a 50–52″ chest in menswear and a 46–48″ bust in womenswear. Usually. The letter is an index into one brand's chart, not a measurement of your body, so the same 48″ chest is a 4XL at one label and a 6XL at the next.
That is the whole problem this site exists for. We track 72 Indian brands, 69 of which publish their own numbers, and read your size off each one rather than guessing from the letter. Name a size you already own and the rest follow — 4XL through 9XL, in inches and centimetres, for men and women.
Below are the size charts, the conversions and the clothing itself, filtered to what is genuinely in stock above 4XL today.