See, there is no specific dress code specified for JEE Mains. So you can wear thermals inside full sleeve t-shirt and lowers.

But you must consider some facts regarding clothes.

Check this link out -

https://engineering.careers360.com/articles/jee-main-dress-code

Hope it helps!

hi,

yes, you may wear cloths to protect from cold. consider the regulations of exam authority,

Do not wear anything which have too many pockets.

Do not wear jewelry.

Wear simple, light color clothes without accessories.

Preferably wear t-shirt and jeans, or top/kurti with leggings.