A 190-year-old Durga Puja in Kolkata is setting a new eco-friendly trend among the city's 'Bonedi' Durga Pujas by becoming the first to immerse its Durga idol in an artificial tank. The tradition in these 'Bonedi Baris' or erstwhile elite households in south Kolkata is to immerse their Durga idols in the Adi Ganga canal, which has been plagued by pollution.