https://timesofindia.indiatimes.com/city/agra/in-up-district...
https://theintercept.com/2020/12/06/kashmir-social-media-pol... this is for tweeting but twitter is a public platform, same as your "mobile number" because twitter forces 2fa that makes you put your mobile for "security" reasons.
what i am trying to say is, this is not about police needing 100% access to find pedophiles. This is about crushing dissent, about the same big brother type are what people in india are seeing unless they join the ruling party. This is out in the open now and has for some time.
This is the way of the government to force big players to comply.
lets say tomorrow signal and whatsapp BOTH remove mobile number requirement. Now, unless the ISP are made to identify their specific traffic and block them on demand, ALL the users would be independent from local indian administrative action