Passengers and crew arriving from North America and Mexico, particularly in flights operated by Air India, Continental Airlines and Delta Airlines, would have to fill a health form and get screened for swine flu at Indian airports, where arrangements are in place to carry out the required medical checks.

According to information by the International Air Transport Association, at least these three airlines would have to provide passenger manifests to the health authorities at Indian airports, particularly at Mumbai and Delhi, for the passengers to be screened.

IATA has said that airlines globally were 'prepared for the heightened level of alert' following the World Health Organization's decision to move to Phase 5 of its pandemic preparedness plan.

The global airlines body and the WHO have prepared guidance materials for the airline staff, including cabin crew, maintenance workers, cleaners, passenger agents and cargo and baggage handlers.

'We are following the advice of the WHO. Safety for passengers and crew is our top priority. People getting on planes should be reassured of two things. First, even under normal circumstances, airlines have equipment and measures in place to keep the cabin environment safe,' Giovanni Bisignani, IATA's director general and CEO said in a statement from Geneva.

For example, modern aircraft have air filtration systems similar to those in hospitals, aircraft are regularly disinfected as part of normal cleaning routines and crew are trained in handling procedures for passengers who might become ill on board aircraft, he said.

Secondly, he said, the years of planning for the possibility of avian influenza have 'prepared the industry to deal efficiently with the unfolding situation by following the recommendations of the WHO.'

The WHO, however, has advised that there should be no restriction of regular travel or closure of borders. 'The WHO is the global expert. The WHO is not advising any travel restrictions. We hope that governments take decisions and coordinate their actions in line with the WHO recommendations,' Bisignani said.

Governments of various countries, however, were 'imposing many new and unilateral measures, impacting both operations and passenger facilitation,' an IATA statement said, adding that some of them were 'adjusting immigration procedures, which can create confusion for travellers.'