In a more charged re-run of last year, the immersion of Goddess Durga idols and Muharram - the Muslim day of mourning - are set for a head-on collision. On Wednesday, Chief Minister Mamata Banerjee addressed a large meeting of Durga Puja organisers, leaders of the Muslim community and other religions. She told them that Durga idol immersions, set for September 30 after the four-day Puja festival ends, would be allowed only till 6 pm on that day and would resume on October 2, after Muharram.