Only brute-force clean-up can save Ambazari lake, says Neeri

Nagpur: There is no magic fix for Ambazari Lake — only brute-force clean-up until sewage stops, the National Environmental Engineering Research Institute (NEERI) told the Nagpur Municipal Corporation (NMC). The expert body's stark assessment exposes the futility of every experiment tried so far to rid the city's largest lake of water hyacinth, while untreated sewage from neighbouring Wadi Municipal Council areas and effluents from Hingna industrial units continue to pour in, fuelling an uncontrollable explosion of weeds.Ambazari lake, spread over nearly 15.4 sqkm, turned into a textbook case of how pollution at the source can defeat even the most aggressive clean-up operations. Neeri clearly advised that physical removal of weeds is the only workable stop-gap solution until the inflow of untreated sewage is completely halted. Anything else, experts warn, merely scratches the surface.
The NMC's public health engineering (PHE) dept says it tried everything in its arsenal. "Several measures were initiated to save the lake from weeds. Cutters were deployed in the past and mechanised systems were used," said superintending engineer Shweta Banerjee. The much-publicised ‘Jaldost' floating weed-removal machine was deployed twice — first when Neeri provided its own unit, and later when NMC hired the machine independently.But the outcome was sobering. "During the cutting of weeds, NMC realised that the weed growth actually doubled," Banerjee admitted, underscoring the scale of nutrient-driven regeneration inside the polluted lake.In a bid to explore chemical solutions, NMC hired a Bengaluru-based firm to spray chemicals across the lake surface. The exercise, which cost the civic body lakhs of rupees, failed to eliminate the infestation. At best, officials said, it discoloured parts of the weed temporarily before fresh growth took over. Another attempt — dragging thick ropes from one end of the lake to the other to pull floating weed mats ashore — also proved ineffective.Even heavy machinery was pressed into service. The solid waste management team of Dharampeth zone deployed a special team armed with poclain excavators to remove weeds manually from accessible edges of the lake. Since 2023, the zone carried out uninterrupted removal drives. Yet, despite the sustained effort, the weed continues to outpace removal.The consequences are now spilling beyond Ambazari. Water hyacinth spread across the Nag river basin, choking the channel from the lake's overflow point to Shankar Nagar and further downstream, raising serious concerns ahead of the monsoon. Officials fear that floating weed masses could block natural flow paths, worsen flooding, and degrade water quality further.Environmental experts say the diagnosis is clear. Untreated sewage — rich in nutrients — creates ideal conditions for hyacinth to multiply rapidly, sometimes doubling in days. Without stopping this inflow, every clean-up drive becomes an endless and expensive cycle. "You can keep removing weeds, but as long as sewage enters the lake, the problem will keep returning," a senior official conceded privately.For Nagpur, Ambazari lake has now become a symbol of reactive governance — crores spent on machines and manpower, but no permanent fix because the root cause lies outside the lake itself. NEERI's warning leaves little room for illusion: until sewage discharge from Wadi is stopped and treated at source, Ambazari will remain locked in a losing battle against weeds — one machine, one contract and one season at a time.