Can any one explain that what is the problem with my cotton plants?

Hi Khalid Farooq as per your images it seems due to the attack of insects. Have you seen any insect there? How many plants are infested?

Yr ap cotton k neechay mulching kar do soil temperature jaldi nhn barha ga nateeja (overirrigation sa nutrient leach down nhn hon ga, soil temperature kum rahna sa roots healthy rahan g, Plant healthy ho ga to pest attack kam ho ga, apka pani kam laga ga ka ap kharch kam ho jya ga mazeed, iska ilawa cotton ko qudarti khad muyasar aya ge. Mulching ap sugarcane ki bakiyat jasa k pata uska ilawa jantar ya jawar ko patariyon par phala kar kar skta han chaha 1 - 2 marla par tajarba kar k dakha result nazar aya ga apko.