S&P Global has updated NHPC Limited's ESG Score to 57 as of Friday.
This is lowered from the ESG score of 61 awarded in February this year.
The revision is in response to the bizarre methane gas explosion in July at an under-construction tunnel in Samardung, Sikkim.
The fatal event saw 25 trapped workers die at the NHPC Teesta Stage-VI Hydroelectric Project site.
The credit rating agency kept NHPC's Environment (E) score component unchanged but reduced it in the Social (S) and Governance (G) categories.