As of October 31st,2012 India and Indonesia were at neck to neck in terms of Facebook penetration and going by the numbers from checkfacebook India is all set to Pip Brazil to the third place with data showing Brazil ahead of India with 120,000 users.
In April 2012, India had over 45 million users which has increased to 60 million by 31st October 2012, which shows that India has added 15 million users in 6 months at an impressive rate of 2.5 million Indian users being added every month.
Indonesia and Mexico rank 4 and 5 with 50 million and 39 million Facebook users respectively