There is a law
Which states for certain countries, your passport must be valid for at least 6 months beyond the end of your intended trip in the US. The reason for this is if you get deported during your trip, the United States must have a guarentee that your passport is still valid for plenty of time so that your own country will take you back. The United States does have reciprical agreements with certain countries under which they will take their own citizens back regardless of whether their documents are expired. Thus, for the countries in that group, the rule is your passport must be valid on the date of entry. However, if your passport is not valid for 6 months, you will not get six full months of admission, but rather only to one day before the expiration of the passport. IT escapes me right now whether India is part of this group, you'll more than likely have to research it on the State Department web page.
