The prime minister's announcement of an open sky policy for flight rights to the Asean countries will come with a lot of strings attached.

Firstly, the civil aviation ministry will insist on a reciprocity clause. A senior ministry official said, "This would not be a unilateral liberalisation. We would also be asking for flying rights for the Indian flag carriers. If that option cannot be exercised due to lack of fleet, we would work out some other alternative arrangement."

• Special: Arm in arm with ASEAN

The official said Singapore Airlines had also objected to awarding daily flight rights to South-east Asian airlines without a commercial agreement.

Singapore Airlines at present had daily flights from the four metros as part of commercial arrangements with Air-India.

Secondly, ministry sources said that the government would allow specific number of flights from specific destinations.

The airlines would be allowed seven flights per week from the four metros and an unlimited number from 18 non-metro destinations like Bhubaneshwar, Patna, Lucknow, Guwahati, Gaya, Varanasi, Khajuraho, Kozhikode, Amritsar, Visakhapatnam and Tiruchirapalli.

The industry, however, has been quite enthusiastic about the move. Thai Airways, which has daily flights from Delhi, three per week from Kolkata and is going to start four flights per week from Chennai soon, now wants to operate daily flights from Mumbai.

Malaysia Airlines too would like to use the offer to operate daily flights out of Delhi and Mumbai.

Currently the airline operates four flights a week from Delhi and Mumbai, seven from Chennai, two from Bangalore and one from Hyderabad.

Royal Brunei Airlines too has evinced interest. Singapore Airlines currently has daily operations from all metros except Kolkata and three from Bangalore.

Its subsidiary Silk Air has three flights each from Hyderabad and Thiruvananthapuram.

The airlines do not seem too interested in non-metro destinations though.

Ministry sources said that the open sky offer that had earlier been extended to US and European carriers too were limited in nature as there were restrictions on number of flights and destinations.

For instance, in the current open sky with the US, the ministry has specified a particular number of destinations. The officials said no country in reality offered an open sky.