The ease with which American David Coleman Headley (49) — who was suspected to have had a hand in the 26/11 attacks and was arrested in the US two months ago — went in and out of India without arousing suspicion made the authorities change visa norms. According to the new regulations that are already in force, a foreign national cannot re-enter India within two months of leaving.

The rule also applies to those who have stayed in the country for 180 days. If a foreign national needs to come back within two months, he or she would require special permission.

The new rule applies not just to multiple-entry tourist visas but to other categories as well. The US embassy message posted on its website that, though the implementation of these rules was inconsistent, Americans should be prepared for the inconvenience and plan their travel accordingly.

The message said: “The US mission received confirmation that foreign passports are now stamped on exit to indicate that the bearer cannot re-enter India within two months of exit unless special permission is obtained from an Indian Embassy, Consulate, or High Commission abroad, regardless of the validity of visa or length of stay.”

The message claimed that Indian authorities even denied re-entry to Americans who exited India for business meetings or for family emergencies.

The British High Commission website also posted an advisory. The site said the new rules caused confusion among its nationals. “Only those considered to have a valid case or an emergency will receive a letter granting them re-entry,” the web post said.

Meanwhile, tour operators were confident that the new regulations would not affect business. Depriving multiple-entry visas to tourists would make little difference to their travel because they would plan a repeat holiday in India a year or two later, they said. Only travellers who wish to visit neighbouring countries and return would face a problem. “But you can always reschedule itineraries,” said Anup Kanuga, western region chairman, Travel Agent Association of India.

The new regulations would increase paperwork only for frequent business travellers. “That is not a big problem because Indian companies dealing with foreign business associates offer guarantees on their behalf,” said Kanuga.