The link [1] links to Telecom Regulatory Authority of India (TRAI) website.
You sign up to DND by dialling a number that is dependent on your carrier (therefore you need to do this separately for all your phone numbers [3]), and go through the "Press 1 for English [2]... Press 2 for so and so... " etc. Takes a couple of minutes.
Once I signed up, the number of marketing and similar silly calls/messages have been nearly eliminated.
Maybe something similar — something that allows people to opt out of such calls/messages — can be implemented in USA.
[1] https://trai.gov.in/faqcategory/unsolicited-commercial-commu...
[2] The language question because there are plenty of languages in India.
[3] Tangent: do people not use multiple phone numbers in USA? Like, I wanted to buy an iphone but it does not support multiple SIM cards (unless you convert one of the SIM to an e-sim [4] which I'm hesitant to do because if I later switch back to an Android phone that does not support e-sim, I'll have to go to my phone company to get a physical sim. Too many hassles. ). Also I'm told iphones sold in China has dual sim capability [5], but I can't go to China just to buy an iphone.