MUMBAI — Devotees began immersing Ganesh idols across Maharashtra on Tuesday as the annual Ganesh Chaturthi festival entered its immersion phase. The Brihanmumbai Municipal Corporation deployed artificial ponds and lifeguards to manage crowds and pollution.

The festival, which honours the elephant-headed deity Ganesha, drew millions to pandals across Mumbai, Pune and Hyderabad. Heavy weekend rain in Ahmedabad and parts of western India, which logged 34mm by Sunday evening, raised concerns about waterlogging and safety at riverside and coastal immersion points.

The BMC set up scores of artificial immersion ponds to reduce the environmental impact of dissolving plaster-of-Paris idols in natural water bodies. The civic body stationed lifeguards, deployed CCTV monitoring at major immersion spots including Girgaon Chowpatty, and coordinated with Mumbai Police on traffic diversions.

Environmental groups have urged worshippers for years to choose eco-friendly clay idols and natural colours. The Maharashtra Pollution Control Board reiterated appeals for community immersions and clay idols to limit contamination of the Arabian Sea and local lakes.

The main immersion, Anant Chaturdashi, falls later in the festival, when the largest idols are carried in processions to the sea. Authorities said the staggered immersions were intended to ease pressure on the final day and prevent the overcrowding that has caused past accidents.