by Rohan Nath
Introduction
West Bengal and particularly Kolkata is renowned for the festival called ‘Durga Puja’ during the period of Navaratri (Fig. 1). The city is decorated with colours, lights and joy for at least 10 days. From the beginning of the sixth day until the ninth day, the ‘pandals’ (the structure where the Goddesses idol are kept) are open for the visitors. The Visarjan or (idol immersion in water) occurs on the tenth day also known as Dashami (Fig. 2).

Based on the Hindu Mythology, the collective energy of all Gods/Goddesses resulted in the emergence of Goddess Durga as an embodiment of Shakti or divine feminine power, to abolish the demon Mahishasura, who possessed the power of immortality against any man or God.
The ceremony of Visarjan is attended by enthusiastic devotees that gather in huge numbers to carry the Goddess Durga to the ‘ghats’ (the banks of the Ganga where numerous religious ceremonies are held) to be immersed in the River Ganga.
The water quality was assessed by researchers, checking for three toxic heavy metals: cadmium, lead and chromium in six major ghats along the Ganga stretch in Kolkata during the pre-festival period and post-festival period.

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Location
Six major zones for immersion were studied (Fig. 3).
Selective heavy metals analysis


Results
The concentration of lead, chromium and cadmium during the pre-festival period and post festival period was analysed (Fig. 4).

Discussion
The immersion of idols has led to a considerable increase in the dissolved heavy metals concentrations in all the six study sites (Table 1).
Table 1.

The tradition of idol immersion has been practised for years in India. Recent water pollution surges have been a matter of concern for the citizens of Kolkata. Several steps can be taken to mitigate the water pollution due to idol immersion:
i. Traditional clay idols should be recommended instead of baked clay idols.
ii. Toxic chemicals and inorganic paints should be banned for painting idols.
iii. Materials used for worship like clothes, flowers, decorating materials like plastics and papers should be disintegrated and collected for recycling or composting.
The government can implement these measures to reduce the level of water contamination and ensure a period of health and festive joy for the people of Kolkata.
Reference 1. Zaman, S., Gobato, R., Pramanick, P., Biswas, P., Chatterjee, U., Mitra, S., & Mitra, A. (2018). Water quality of the River Ganga in and around the city of Kolkata during and after Goddess Durga immersion. Parana Journal of Science and Education, 4(9), 1-7.