Ganesh idol immersion pushes up pollution levels in Hyderabad’s Hussainsagar

Ganesh idols being lowered into the waters at Tank Bund on the final day of immersions, in Hyderabad.

Water quality in Hussainsagar deteriorated during the Ganesh idol immersion period in September, with turbidity, suspended solids, and chemical and biochemical oxygen demand increasing at all six monitoring locations, according to the Telangana Pollution Control Board (TGPCB).

The board collected samples before, during and after the immersion period as part of a monitoring exercise prescribed by the Central Pollution Control Board. Samples were collected on September 11 before immersion, on September 17, 19, 21 and 23 during the immersion period, and finally, on September 28 after immersion.

The highest turbidity of 200 NTU (Nephelometric Turbidity Unit) and chemical oxygen demand (COD) of 164 mg/L were recorded at Necklace Road during the immersion period. Total suspended solids (TSS) peaked at 99 mg/L at Platform No. 1 opposite NTR Park.

While these parameters declined after the immersion period, they did not return to their pre-immersion levels. Biochemical oxygen demand (BOD) also increased at all six locations during and after immersion.

The analysis further showed a significant increase in total coliform bacteria at all monitoring points during immersion. Though levels declined at some locations afterwards, they remained elevated at the two platforms opposite NTR Park. Faecal coliform levels also increased at four locations during immersion and remained above pre-immersion levels even after the festival.

At Lumbini Park, faecal coliform levels increased further after immersion. The Board, however, found no significant changes in dissolved oxygen levels in the lake.

The six monitoring points included two locations opposite NTR Park, Lumbini Park, Necklace Road, the immersion point near Lepakshi Handicrafts and the Buddha statue area, which served as the control point.

The board noted that rainfall on September 14, 19, 20 and 22 led to runoff from catchment areas entering the lake, contributing to variations in parameters such as COD, BOD and hardness.