The civil aviation ministry and the Directorate-General of Civil Aviation (DGCA) seem to have finally woken up to the two biggest problems bogging down the the country's two busiest airports, Mumbai and Delhi—delays and congestion.

The authorities have read the rule-book to the airlines and most of the guidelines they have been asked to follow are based on some practices being followed by major international airlines.

A meeting, convened by civil aviation ministry joint secretary Alok Sinha, for the implementation of a host of measures to cut down on delays, came off in the city on Thursday with the authorities asking airlines to stick to time schedules or lose their slots in the line-up for departure. The DGCA has asked for departure slots at the airport to be evenly distributed so that flights do not bunch up. According to the circular, there should not be more than five departure slots in 10 minutes and 30 in an hour.

"This is basically aimed at reducing the congestion in the morning and evening when there is a long queue of departing flights. If the slots are evenly divided there will be no bunching up of flights,'' an airport official said.

The DGCA said no new route or slot would be sanctioned for Mumbai till runway conditions improved. "The airport cannot conduct round-the-clock cross-runway operations. In October, the main runway is also supposed to go for recarpeting. This means that flights and the distribution of loads have to be carefully planned, keeping in mind the infrastructure,'' an official said.

The circular also says the Air Traffic Control (ATC) should not accept a flight plan by an airline if it is other than its stipulated, approved slot. "For such cases, alternative slots will be allocated by the ATC, based on the availability of vacant time schedule,'' the circular states.

At present, the system of getting a departure slot is flexible and, if an airline cannot operate in a certain hour, it can ask for another slot. "However, the slot it might ask for may not be necessarily vacant. This increases the load, leading to delays,'' an official said.

An aircraft preparing to take off, has to contact the clearance delivery unit (CDU) for ATC clearance, not before 45 minutes and not later than 15 minutes prior to the schedule. The approval for push-back—when an aircraft leaves the parking bay and heads for the taxiway—will be valid only for 5 minutes and the flight would be sent to the end of the queue if it fails to adhere to it.

"Usually, airlines take it easy as there are no punitive measures. The push-back is announced much in advance only to keep a certain slot occupied, when in reality, the boarding gates are still open. Moreover, clearances are sought at the last moment. This makes the process disorganised. The rules look at smoothening the operations at the airport,'' a DGCA official said.

Incidentally, these rules were released in an Air Transport Circular dated October 21, 2009. But they were never followed and complaints of delays at Mumbai and Delhi have now spurred the ministry into action. "The meeting, which was attended by all officials was aimed at implementing the old circular,'' an official said.