Historically Soviet Union (and later Russia) had been a reliable partner for India, specially during crisis and on tricky issues (Nuclear...). While US and west generally aligned with Pakistan.

During the India Pak war of 1971, US and Britain had their ships near Indian waters to threaten India. While it was Soviet that sent ships to support India. http://www.theworldreporter.com/2011/10/1971-india-pakistan-...

Russia collaborated with India in setting up nuclear reactors when the west was imposing sanctions.

https://www.orfonline.org/research/india-civil-nuclear-agree...