I will be traveling to India and am in the process of making bookings go to the different destinations. From what I remember there are two airports in Delhi, but I am not too sure whether domestic and international have merged, so I need to know how many airports in New Delhi? This would make it less confusing for us when we arrive at New Delhi and need to leave New Delhi.
There are three different airports but only two are used for commercial flights. International airport is terminal 3 and the other one is just for domestic flights. International terminal is only about five mins drive from domestic terminal. There are lots of domestic flights also from the international terminal so try getting one of those flights so you wont have to go to the other airport.
To add to the above answer, there is one airport which is used for commercial flights, but it is split into domestic and international terminals which are located quite far apart. The other two airports are used for defence and private aircraft respectively and are off bounds for most civilians. If you are visiting India you will land at T3 of IGI airport. It is one of the newest and best terminals in the country, so it should be a smooth experience.