Hydration needs increase significantly in summer. Plain water is still best, but electrolytes lost through sweat need replenishing. Coconut water, lemon water with a pinch of salt, and buttermilk are practical Indian options providing fluid and electrolytes without added sugar.
Move outdoor activity to early morning or evening. Cotton and linen fabrics breathe significantly better than synthetic materials. If you notice dizziness, nausea, and cessation of sweating during exertion in heat, this is a heat stroke warning requiring immediate cool shade and water.