The ban has been active in Bangalore since March, 2016 [1] and in Mangalore for much longer [2]
I was surprised to learn Delhi did not have such a ban so far
[1] http://timesofindia.indiatimes.com/city/bengaluru/Total-plas...
[2] http://www.thehindu.com/news/cities/Mangalore/mangalore-bans...