India, Aug. 19 -- To most international travellers, the concept of travelling to the United States visa-free may seem too perfect to be real. But to millions of travellers, it has already been done with the Visa Waiver Program (VWP).

The program enables the citizens of the participating countries to stay for up to 90 days in the US without acquiring a visa.

Visa Waiver Program is an exceptional agreement between the US and the selected countries. Citizens of these nations do not have to obtain a visa to visit on short-term basis, although one thing remains to be done, which is obtaining the authorisation with the help of Electronic System of Travel Authorisation (ESTA).

ESTA is not a visa, but it is compulsory, and flights will not all...