The National Green Tribunal (NGT) has directed Delhi and four neighbouring states to urgently restore native fish populations in the Yamuna river and take strict measures to control the spread of invasive, non-native species that are rapidly altering the river’s ecosystem.
The order, passed on January 29, came after the tribunal took cognisance of a media report highlighting the alarming decline of indigenous fish species and the unchecked rise of exotic varieties in the river. Acting on the findings, the NGT asked Delhi, Uttarakhand, Himachal Pradesh, Haryana and Uttar Pradesh to implement recommendations submitted by the Indian Council of Agricultural Research–Central Inland Fisheries Research Institute (ICAR-CIFRI).
The directions are based on a detailed survey conducted by ICAR-CIFRI, Prayagraj, between 2020 and 2024, which recorded 126 fish species along the Yamuna stretch from Yamunotri to Prayagraj. The study found that native species such as Catla, Rohu, Mahseer and eel are steadily declining, while invasive species including Common Carp, Nile Tilapia and Thai Mangur have proliferated, particularly in heavily polluted sections of the river.
The tribunal noted that pollution remains one of the primary reasons behind the decline of native fish species. A bench headed by NGT chairperson Justice Prakash Shrivastava observed that degraded water quality and disrupted river flow have severely affected fish breeding and migration patterns. The tribunal also called for the construction of fish ladders at major barrages to allow native species to migrate freely along the river.
As part of its recommendations, ICAR-CIFRI suggested banning juvenile fishing and illegal fishing gear such as mosquito drag nets, strengthening monitoring during fishing ban periods, and maintaining systematic records of fish catch data. The institute also proposed strategic ranching of native Mahseer in the upper stretches of the Yamuna, Indian Major Carps and other commercially important species in the middle and lower stretches, and air-breathing fish in designated sections within Delhi.
Additional measures include improving overall water quality, ensuring continuous monitoring, maintaining minimum ecological flow, regulating sand mining activities and strictly prohibiting the breeding and spread of invasive fish species.
The issue had earlier been flagged by *Hindustan Times* in July 2025 at Wazirabad, the last designated fishing point of the Yamuna in Delhi. Local fishermen had reported a sharp decline in indigenous fish such as Rohu, Singhara, Catla and Malli, noting that the few fish surviving in the river were largely invasive species that had adapted to polluted conditions.
Tirmal Singh, a 62-year-old fisherman from the Mallah community, said the transformation of the river’s ecosystem has been stark. “Until the early 2000s, we could still catch Rohu or Singhara here. Now they have completely vanished,” he said, adding that fishing livelihoods have been severely impacted over the past two decades.
The NGT said the implementation of scientific restoration measures was essential not only to protect biodiversity but also to safeguard the livelihoods of communities dependent on the river, stressing that delays could lead to irreversible ecological damage.