Margins are going to increase in phased manner from December 1st, not straightaway.
As explained in this post.
This SEBI circular says that there will be a penalty if trades are allowed without sufficient VAR+ELM or 20% for stocks, and SPAN+Exposure from Dec 1st 2020 even on an intraday basis.
- Dec 2020 to Feb 2021 - penalty if margin blocked is less than 25% of VAR+ELM ( or 20% of trade value) for stocks or SPAN+Exposure for F&O. (Max leverage of 5% or 20 times for stocks)
- Marc 2021 to May 2021 - penalty if margin blocked less than 50% of minimum margin required. (Max leverage of 10% or 10 times for stocks)
- June 2021 to Aug 2021 - penalty if margin blocked less than 75% of minimum margin required. (Max leverage of 15% or around 7 times for stocks)
- From Sept 2021 - penalty if margin blocked less than 100% of minimum margin required. (Max leverage of 20% or 5 times).
The above essentially means that in a phased manner the broking industry will move to a structure where intraday leverages offered can’t exceed what is already offered by VAR+ELM (or 20%) for stocks and SPAN+Exposure for F&O by Sep 2021.
You won’t need full SPAN + Exposure from December 1st, you will need 25% of SPAN + Exposure from December to February, from March to May you will need 50%, from June to August you will need 75% and from September 2021, you will need full SPAN + Exposure margin.