Five monitoring centers have been set up by local environmental departments to keep close watch over the air and water quality around the site of a gas blowout Tuesday near Chongqing,southwest China.

As of Sunday morning,monitoring data had been obtained by 66technicians from the State Environmental Protection Administrationand local environmental departments.

The gas blowout took place at 10:00p.m.Tuesday and killed at least 198people,when a well blew out suddenly and released high-concentration natural gas and sulfurated hydrogen at Chuandongbei gas field in Kaixian County,some 337kilometers northeast of Chongqing.

After the gas well was successfully sealed on Saturday,four monitoring teams were sent by the municipal environmental department to begin monitoring.