Moving to Singapore

As usual with cost of living questions, much depends on your daily spending choices.
You can spend S$400/month to rent a bed (bunk) in a room shared with six others, or S$2000 for a room in a (shared) luxury Condo.
Pubbing (as anything involving entertainment and especially alcohol) is an extremely expensive hobby in Singapore - consider at least S$200 for an evening in a Disco with two/three drinks, some snacks and the taxi ride home. You can easily spend a multiple!
Cooking yourself costs more than eating at the very economical hawker centres, where you can find many kinds of food at S$5-8 for a meal (incl. drink).
I'd estimate you need S$800-1000/month for daily expenses (simple lifestyle, no pubbing, travelling, alcohol, smoking, no family or girlfriend to entertain) and S$800-1000/month to rent a room with shared bath in an HDB flat.
To save a hundred thousand Indian rupees a month (which is over S$2100/month), add that amount to the monthly living expenses plus this amount (and 4-8% for taxes, insurance, etc.).