New DelhiAirlines were on Monday asked to take additional steps for passenger convenience and the Delhi airport was directed to accelerate work on one of its runways that can handle low-visibility landings as weather-induced delays and cancellations continued on Monday, prompting the government to step in.

Between Sunday and Monday, close to 600 flights were delayed and 100 cancelled as dense fog shrouded the Capital, with visibility at times dropping to zero metres, a condition in which even specialist low-visibility instruments are unable to maintain operations.

Civil aviation minister Jyotiraditya Scindia described the fog spells as “unprecedented” for the Indira Gandhi International (IGI) Airport, and said authorities had to therefore enforce brief shutdowns of operations for passenger safety.

But, he added, two measures have been taken to ease the situation soon: First, he said, Delhi Airport has been asked to “immediately expedite the operationalization of the CAT III-enabled 4th runway (in addition to the existing CAT III-enabled runway)…”

And, second, he added, the aviation regulator directorate general of civil aviation (DGCA) “will issue an SOP for airlines on better communication and facilitation of passengers to minimise discomfort in view of flight cancellations and delays due to adverse weather”.

Scindia acknowledged the difficulties people were facing but assured the public that “all stakeholders are working round the clock to minimise the fog-related impact”.

Social media showed several angry passengers arguing with airport staff in New Delhi and other airports and one video showed a man assaulting an IndiGo airlines pilot who was announcing a delayed flight on the aircraft. Passengers of another IndiGo plane were seen having their meals on the tarmac next to their plane at the Mumbai airport, where it was diverted while on its way to Delhi from Goa due to the conditions in the national capital.

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Referring to the assault in the IndiGo airlines plane, Scindia said: “Incidences of unruly behaviour amidst this are unacceptable, and will be dealt with strongly in line with the existing legal provisions.”

The attacker, Delhi shopkeeper Sahil Kataria who was headed to Goa on vacation, was offloaded, arrested, and later released on bail.

DGCA, later in the evening, sent SOPs over email asking airlines to give flyers realtime information on schedules and delays, sensitise staff at airports to appropriately guide passengers during a delay, and to cancel a flight well in advance if they anticipate long delays during service.

“In view of the prevalent fog season and adverse weather conditions, airlines may cancel, sufficiently in advance, such flights that are anticipated to be delayed or consequentially delayed on account of such conditions beyond a period of 3 hours with a view to obviate congestion at the airport and mitigate passenger inconvenience,” said the email sent by DGCA’s AED director Amit Gupta .

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The other step pertains to the work underway on runway 29L/11R, which is one of two runways (of a total four) with CAT-III landing instrument compatibility, which allows pilots to land even in low visibility. At present, only the runway 11L/29R is functioning with CAT-III instruments, but landing or taking off from this becomes hazardous when visibility is determined to be zero metres.

Cascading effect of issues

Current and former pilots as well as officials involved in airport security said there are several issues involved. First, passengers face the most inconvenience when they are boarded and have to wait with the plane having closed its doors for take-off.

A senior pilot, who asked not to be named, said airlines usually do not ask passengers to get off the plane even in the case of a massive delay for two reasons: First, they do not want to redo the entire check-in and security clearance procedures, and second, they do want to miss their number on the sequence of departure – which is allotted only when all passengers are seated and doors close.

“If an airline de-boards its passengers, then, as per rules, they are not taken to the boarding area, but to the arrivals. The passengers have to mandatorily clear security check before they are allowed to enter the boarding area. This is a cumbersome process, which the airlines want to avoid,” this person said.

A former DGCA official said that the Bureau of Civil Aviation Security (BCAS) rules mandates that a passenger can be allowed back into a boarding area after they are frisked again. But, “if the airport consists of a domestic to domestic (D-D) transfer area, then a passengers need not be asked to check-in again. He/she can be frisked by the CISF after which they can be allowed to remain in the boarding area”.

Mohan Ranganathan, an aviation safety expert, said: “Airlines seem to be playing with a loophole in the rules.”

Ranganathan said no rule mandates airlines to force passengers to check-in for their flight again and agreed the internal transfers area can be used to directly reach the security area.

Commenting on the SOPs issued by DGCA, Ranganathan said: “One thing missing is action for de-boarding passengers. If delay exceeds a certain time, passengers must be provided refreshments once they check-in, irrespective of whether their tickets specify entitlements or not. Airlines must also inform passengers at the time of check-in if there is a long delay expected.”

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Fog may persist: IMD

The bad weather also caused chaos in train schedules. At least 18 Delhi-bound trains were reported running behind schedule due to fog, railway officials told news agency ANI.

Triggering the travel chaos is a large patch of dense fog that has shrouded the entire Indo-Gangetic plains, stretching from Pakistan to the Bay of Bengal in the east since Sunday.

The chill and fog are both unlikely to relent over the next few days, said the India Meteorological Department (IMD) as it issued an orange alert over Delhi for Tuesday and Wednesday. An orange alert, which was also in place on Monday, warns people of inclement weather and of potential disruptions to everyday life.