Do Client has to compulsory maintain 50% Cash collateral for F&O trading from 28 FEB 2022 onwards ?

50-50 cash to collateral ratio is applicable only for overnight trades. The exchange will start levying penalties from August 2022 in the event that you don't maintain this ratio. However, you can trade with a higher collateral component as you must be doing right now in the intraday timeframe without any changes. 

https://support.fyers.in/portal/en/kb/articles/does-fyers-provide-collateral-margin-against-holdings-securities227