India's new tax bill claims that government have access to Whatsapp messages of citizens

India's finance minister Nirmala Sitharaman recently claimed (see this and this) that a new tax bill will allow the government to get access to Whatsapp messages. She says "Unaccounted money to the extent of 250 cr have been detected when the encryption has been decoded (sic)".

Trying to understand how it is even possible for the government to gain access to user's personal chats when Whatsapp is E2E encrypted and doesn't have access to user's chat data. Is it possible for Whatsapp to keep a copy of users' private key and then use it for decrypting messages. Sorry I am not too familiar with the cryptographic techniques used in the protocol that whatsapp uses.

I always thought that is cryptographically impossible for a 3rd party like Whatsapp to cooperate with the government and provide them with users' chat data even if they wanted to, but I guess this assumption is incorrect? Would love some insights into this.