Most expats think that the cost of living in India will be super cheap - not the case. Especially if you're living in Delhi. Housing is super expensive, and can eat up a fair portion of your monthly salary. See if you can get your company to cover this or to give you some sort of housing allowance. Also, if you have kids, international schools can be costly. Again, check on getting an allowance or an education subsidy. Otherwise though, the cost of living in Delhi can be pretty decent. Food is cheap, but not Western-style food (like dips and cheeses and pasta).
For more info read the Expat Arrivals Cost of Living in India page.