Authorities in Mumbai stepped up security at the Chatrapati Shivaji International Airport (CSIA) following a terror alert received by the Maharashtra government.
All states bordering Maharashtra were also directed to go on full alert following intelligence reports that the airport may be targeted by attackers using small aircraft or helicopters.
"In general, security has been beefed up at the airport with Central Industrial Security Force (CISF), Bureau of Civil Aviation Security (BCAS) as well as the Mumbai Police in charge of the security," said an airport spokesperson. "Flight operations are however normal," she added.
State police at Maharashtra, Gujarat, Madhya Pradesh, Karnataka and Goa were directed by central security agencies to remain on high alert to foil any possible terrorist plans to attack Mumbai airport.
Police chiefs were told to subject all aircraft to thorough security checks before they are cleared for takeoff.
The police were also told to also keep a tight watch on unused airstrips and helipads
The unscheduled visit of Union Home Minister P. Chidambaram to Mumbai is seen as an indication of a review of the security situation in the city.
The high alert came after an email was received by media organisations saying that the recent Delhi High Court blast was a warning of an impending attack in Gujarat on September 13.
Although, it has been found that the e-mail was a hoax, police are taking no chances. Precautionary measures are also being taken in view of the third anniversary of the September 13, 2008, blasts in Delhi that claimed over 20 lives.