This means that only the far-month July and beyond expiry contracts will be revised for market lots.
In the options market, buyers were missing.
"Do not see a reduction in market lot size for Bank Nifty impacting markets.
However, it will benefit traders who are looking to trade in lower quantities and not traders who are trading in higher volumes.
The aim of the NSE is to keep the lot size for F&O at 5 lakhs as per their rule book," said Chandan Taparia, head of technical and derivatives research at Motilal Oswal Financial Services Ltd. The only concern is that Nifty and Bank Nifty will lose the parity they had earlier, as there will be a difference in the value of the lot size of both of these indices.

Source -https://www.bqprime.com/markets/nse-cuts-nifty-bank-futures-and-options-market-lot-size