hi,

you have mentioned that the validity period of your ews certificates is 1 year. so since it has issued on 16 December, 2020, it would be valid till 16 December, 2021. now the counselling process of b.tech would start on august 10, be analyzing the general counselling time, it would take maximum of 1.5 month to complete. so at this period of time your certificate would valid and you should not face any issue regarding the validity of ews certificate.

hope it would help.