Hi @vkhaitan
Brokers collect VAR/ELM/Adhoc or any other additional margin as per Exchanges/CC since those margins gets blocked at CC level for brokers and in turn broker collects from clients. Otherwise it would be treated as funding which can only be under MTF and not for general shares as pledge (collateral). The above shared SEBI master circular covered this point.
Exchanges/CC can term the Special/additional or any margin as per their terminology like Adhoc margin, etc.
**Now its T+1.
I guess you had referred this thread on similar query on how brokers charge different haircuts, just linked again here if that helps.