Ganesh Chaturthi is the best time of the year to visit Mumbai if you don’t mind crowds (I mean crowds by Indian standards which is very different compared to say European or Canadian standards). The city buzzes with activity as people prepare to bring home an idol of the elephant-headed Lord Ganesha, worship it for a few days, and then give the Lord a grand send off
It might be the biggest farewell party you’ve seen. To read more about this interesting festival, its customs, and etiquette if you are invited for a pooja, go through this post.