Mock terror and chemical attacks were carried out simultaneously at various stations of Delhi Metro early Thursday morning to check the emergency response of various agencies involved in disaster management.

Monitored by the National Disaster Management Authority, the mock drills were carried out simultaneously at Rajiv Chowk (terror attack), Chawri Bazar (toxic gas release), Rithala (bomb blast at parking area) and Shastri Park (call about planting of bomb at train depot) at around 6:15 am.

"The Metro system anywhere in the world is a lucrative target and we decided to carry out the mock drill here to review the efficacy of various agencies like Metro, district administration and police in such scenarios," NDMA Vice Chairman Gen (Retd) N C Vij said.

This is the first time a mock exercise on disaster management is conducted in the capital, which used multi-hazard situations to review efficacy of state and district administration in responding to the problem.

At Rajiv Chowk station in Connaught Place, a mock attack was carried out by four persons attired in CISF uniform opening fire and throwing grenades at the passengers' platform.

The 'attackers' also then managed to partially switch off the lights at the platform, with complete darkness prevailing in station control room.

"The idea of this exercise was to assess how personnel of DMRC and CISF responded, how efficiently police cordoned off the area and how fast the administration was in setting the incident command post," NEDA member J K Sinha said.

Chawri Bazar, Metro's deepest station located 120 feet down from surface, was subjected to a 'chemical attack', believed to be the release of highly-toxic Phosgene, during which the efficiency with which authorities evacuated passengers were checked.

During this exercise, the members of the newly set-up National Disaster Response Force participated for the first time in a mock drill by the setting up a decontamination centre.

The third drill was carried out at Rithala station where mock car and motorcycle blasts were triggered at the parking area by using crackbusters and smoke candles.

Fourth one was done at Shastri Park to assess how Metro and district administration respond to a call threatening to blow up train depot located in the station.

Vij said the exercise did not have the 'surprise' element in it as it was an attempt to rehearse and evaluate the standard operation procedures of various stakeholders.

"It was not an effort to find fault with anyone but review efficacy of agencies," he said.

Independent observers of NDMA were present at the stations, who checked how the metro officials were giving information to passengers through public address system, stop movement of the trains, informed police and how other agencies operated during the crisis.