New Delhi, Jul 22 (PTI) The National Green Tribunal has asked the National Mission for Clean Ganga (NMCG) to explain the basis for the criteria it used to demarcate the Ganga River’s floodplain in Varanasi, noting potential discrepancy between its adopted methodology and rules.
A bench of NGT Chairperson Justice Prakash Shrivastava and expert member A Senthil Vel was hearing the matter regarding an alleged illegal construction by M/s Sri Wari Chemicals Private Ltd inside the active floodplain zone at Ramghat in Varanasi.
The applicant’s counsel, Saurabh Tiwari, had earlier alleged that the said construction violated the restriction put by the Allahabad High Court and the River Ganga (Rejuvenation, Protection and Management) Authorities Order of 2016.
In a July 20 order, made available on Wednesday, the bench noted that the NMCG had filed an affidavit on July 15 in pursuance of the tribunal’s earlier directions.
According to the affidavit, the bench noted that the NMCG had requested Uttar Pradesh to undertake the requisite hydrological and technical studies through the competent authority and “complete the demarcation of the floodplain corresponding to the one-in-five-year and one-in-25-year return periods (of floods).” The NMCG affidavit said it had cited technical guidelines issued by the Central Water Commission (CWC) in July 2025.
A one-in-five-year flood (or five-year recurrence interval) is a flood event with a 20 per cent probability (one in 25 probability) of happening or being exceeded in any given year.
Similarly, a one-in-25-year return period flood (or 25-year recurrence interval) is a flood that has a 4 per cent chance (one in 25 probability) of occurring or being exceeded in any given year.
The tribunal said, “The active floodplain has not been defined in the Ganga Rejuvenation Order, 2016. Hence, NMCG is required to clarify on what basis it has sent the communication to the State of Uttar Pradesh for demarcation of floodplain corresponding to 1 in 5 years and 1 in 25 years return periods (of floods), which does not align with the Ganga Rejuvenation Order.” According to Clause 3(I) of the 2016 order, the floodplain is to be defined taking into account the 1:100-year highest flood level.
A 100-year flood means there is a 1 per cent chance that a specific flood level will be equalled or exceeded in any given year.
The green panel further pointed out that while the CWC guidelines of July 2025 were cited, those documents had not been placed on record.
The mission’s counsel was then allowed four weeks to produce the relevant guidelines.
The tribunal also allowed advocate Tiwari’s request to implead the Ministry of Jal Shakti and CWC as respondents or parties.
The matter has been listed for further hearing on September 21. PTI MNR RHL
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