This is the result of one of the biggest vaccination drives ever. Great work by India's central governement, various state governements, WHO, UNICEF, Rotary International and various other NGOs and volunteers.
I suppose they may have only been involved since 2009, however the Foundation has already contributed $1.2 billion with another 1.8 billion on the way.
Of course, as you mentioned, much credit goes to "various governments, the WHO, Rotary International, the U.S. Centers for Disease Control and Prevention and Unicef."
The work done by the Gates foundation is admirable. But the $1.2 billion was donated to the Rotary International for the Global Polio Eradication initiative, not exclusively to be used in India. In fact, it's not even clear if any of that was used in India at all. Moreover India itself has donated $1.3 billion for the Global Polio Eradication initiative.
The Gates foundation offered a $100 million matching grant to Rotary International's Polio Plus program in 2009. The intial matching grant and subsequent increases have been matched by Rotary's members.
Rotary international is a huge help. I've volunteered as a vaccinator over the summer last year. In the 2 months I was there, we traveled to over 14 cities, and vaccinated well over 10,000.