A year has passed since a gas leak on April 30, 2023, in Ludhiana’s Giaspura killed eleven residents, including three minors. Still, authorities have not identified the gas or its source.
Preliminary evidence suggested that the cause of death was asphyxia (deprivation of oxygen) due to inhalation of a poisonous gas (which could be hydrogen sulfide or a combination of gases). The National Green Tribunal (NGT) constituted two Joint Committees to investigate the matter.
The first report cited damaged sewer infrastructure, ineffective sewer cleanup, and temporary blockage due to materials deposited by heavy rainfall as possible reasons. It said there was a strong possibility that the sewer line was blocked in the affected stretch, which caused the gas to accumulate and escape. NGT rejected this report, calling it “unconvincing”. It found inconsistencies in the responses recorded by the Central Pollution Control Board officials.
CPCB Regional Director had stated that the prolonged deposition of sludge in the sewer line may have created anaerobic conditions, leading to the build-up of high concentrations of H2S. However, other CPCB officers found that the low pH levels reported in the main sewer water near the site could be due to acidic industrial effluent discharge.
So, the NGT constituted a fresh committee, comprising of experts from the Union Ministry of Environment, Forest and Climate Change, CPCB and IIT Delhi. They released their report on March 4, 2024, noting that the gas leak happened due to leakage or emission of sewer gas. It has not ruled out the possibility of acidic effluent being discharged into the sewer. The report stated that the toxic H2S sewer gas could have travelled into the branch sewer connected to the houdis (escape points of gases released from the sewer pipeline) of the affected houses.
The report also considered post-mortem reports, which stated that the cause of death was poisoning due to toxic gas inhalation. However, the reports could not pinpoint the type of poisoning as further analysis is still awaited. Meanwhile, Nand Kumar Sahu, a resident of the area told Down To Earth that no improvements have been made to the sewer system since the incident and the cleaning was last done six months ago.