What happened to my cotton plant and what is the solution of this problem

Sukhdev Singh have you treated with pesticides lately? Can you send more pictures please?

https://youtu.be/qaq4gCNov2A

Your plants look like they are suffering from problems from application of a pesticide. To minimize the damage add aged manure or compost.

Also make sure to give your plants plenty of water and do not treat with pesticide again at least until the plant is healthy again. I understand that there are problems with crops in your area, but a second application at this time will most likely kill your plant. Remeber to use as little pesticide as possible as plants also suffer from these chemicals. Also if you apply these chemicals to do so only in early morning or early evening when the sun is not so intense. I hope this helps

Fertilizer will help to minimize the damage also which is why I suggest aged manure or compost but almost any fertilizer for cotton will be good at this point

No no. Not pesticides. If those are being appiled that may be compounding the issue...but first things, first.... - where are you located? - your soil looks like topsoil from Wal-Mart. What type of media are you working with? -did you start seed in this or did you transplant? Either way...when? -stop flooding the trenches...

Interesting Artur...I have not heard of that one yet. Hmmm...perhaps. But, regardless...the bottom line is the soil and irrigation is causing this issue...the plant WAS growing before something "nipped" it...