NEW DELHI:  A domestic flight arriving at New Delhi's international airport landed on the wrong runway even though air traffic control was guiding it to the main airstrip, an airport official said on Wednesday.

The SpiceJet flight carrying 160 passengers and crew arriving from Kashmir was being guided by air traffic to the main runway Tuesday afternoon but veered off to an auxiliary runway and landed manually, he said.

"It's not clear whether the instrument landing system was faulty or whether the pilot himself chose to land manually," said an executive for the privately-run Indira Gandhi International Airport, asking not to be named.

"The two runways are basically next to each other. He mistook the secondary runway as the main runway. Fortunately the runway was absolutely clear. There was no obstruction that would have impeded the craft."

India's civil aviation agency and the airline were examining the incident, the executive said. 

"Obviously this is a serious matter. The Directorate General of Civil Aviation and SpiceJet have decided to look into this," he said.