This looks accurate, for electrical sockets:
https://3.imimg.com/data3/RC/IC/MY-8188578/electric-sockets-altima-2...
The first 2 types in that image are 5 Amp sockets, and the third type is a 15 Amp socket. Hotel rooms would probably have the first 2 types. The first type supports both the 3-pin and 2-pin plugs. The third type is meant for heavy duty appliances, so hotel rooms are unlikely to have those.
3-pin plug: http://www.signalandpower.com/images/zoom/P-8012-06B.jpg
2-pin plug: https://4.imimg.com/data4/CQ/SF/ANDROID-1651946/product-250x250.jpeg

ATMs are plenty within the city. You could easily find one on every street. There are many ATMs right at the airport.
Nearly all the ATMs accept international debit and credit cards from Visa and MasterCard. Few ATMs work with American Express cards as well.
The venue for WSC/WPC is on the outskirts of the city, so there would likely be fewer ATMs around. A quick Google search shows up 2 ATMs (HDFC, SBI) that are located about 1.5 Kilometres from the venue.
A quick note. Try to get notes of lower denominations (Rs. 500, Rs. 100, Rs. 50) from ATMs. Most of the ATMs are stocked with Rs. 2000 notes these days, and it is hard to get change for those.