First off, I am a bit biased as I've got family there and
have been there several times. The communists only became a force in the later days. In 1948, they had little chance of taking over India or launching a revolution. The COngress party was the most powerful and had no serious rivals except for the Muslim League, which campaigned for and won a separate Muslim state which today is Pakistan.
Even today, they are only powerful at the state level. They aren't a national level political party like the Congress or BJP and are merely useful as a coalition partner. Also, socialist policies in general have cost India dearly these past 50 so years. Driving out foreign investment that could have created jobs, driving out foreign investment that could have spread technology, destroying any chance of useful relations with the US as a buffer against China, trying to be buddies with China and first losing Tibet as a buffer zone and then some of its own territory in a short war, and keeping the country mired in poverty when it could have become so much more. The only positive has been a large, english-speaking, and well educated pool of professionals. The communists at the local level have fostered good education and very good agricultural policies when they did land reform versus wholesale collectivization. However, I think their best example was in WEst Bengal (this state includes Calcutta) where after initially being very against foreign investment, they saw how Banglore and Hyderabad in the south were taking off and started trying to attract IT companies in a manner similar to that done in China. Hopefully, it will turn out for the better. I hope that the Communists turn out to be more like those in CHina as opposed to Stalinists but right now, some of their horribly inept politicians such as the infamous Laloo Prasad Yadav make a mockery of government to say the least. Like anythign in India, they are rather full of contrasts.