Ganesh idol immersion in Hussainsagar led to a rise in pollution indicators, including suspended solids and bacterial levels, according to TGPCB. (Representational image)

Ganesh idol immersion in Hussainsagar led to a rise in suspended solids, oxygen demand and bacterial levels in the lake’s water at all six monitoring points, with several readings staying above pre‑immersion levels even a month after the festival, according to the Telangana Pollution Control Board (TGPCB).

The board’s analysis recorded the highest turbidity and chemical oxygen demand (COD) at Necklace Road, where turbidity touched 200 NTU and COD stood at 164 mg/litre during immersion.

Monitoring covered six locations: two platforms opposite NTR Park, Lumbini Park, Necklace Road, near Lepakshi Handicrafts and the Buddha statue midstream. Samples were collected on September 11 before immersion; on September 17, 19, 21 and 23 during immersion; and on September 28 after immersion. The festival was held on September 14.

Total suspended solids (TSS) increased at all six locations, peaking at 99 mg/litre at Platform No. 1 opposite NTR Park. Though turbidity and solids declined after immersion, they did not return to pre‑immersion levels. Biochemical oxygen demand (BOD) rose at all six locations during and after immersion. COD also increased significantly and remained above pre‑immersion levels.

The board found a sharp rise in total coliform bacteria at all six locations. Levels declined after the festival at Necklace Road, Lepakshi Handicrafts and near the Buddha statue, returned to pre‑immersion levels at Lumbini Park, but stayed elevated at both NTR Park platforms.

Faecal coliform levels rose during immersion at four locations — the two NTR Park platforms, Necklace Road and near the Buddha statue. Though they declined afterwards, they did not return to pre‑immersion levels. At Lumbini Park, faecal coliform levels increased further after immersion.

Despite the rise in several indicators, the TGPCB found no significant change in dissolved oxygen levels. The board also noted rainfall on September 14, 19, 20 and 22, which brought runoff from catchment areas into the Hussainsagar and may have contributed to variations in COD, BOD and hardness.

TGPCB said it would continue scientific testing and monitoring of water resources and appealed to the public, government departments and festival organisers to cooperate in protecting the lake.

Tags: