The cost of living in Chennai will depend on the number of people who are going to live there. For example, if a couple is going to live in Chennai, expect that it will cost about 40 - 50 thousand. The cost will go higher if the family is bigger. There may be more to spend on like the children’s education.
There are moments when people would also like to go on vacation so this can be included in the 40 - 50k with just a few changes to the funds that are already arranged for food and sometimes, transportation. The money that will be spent on the house and other necessities may change depending on the area in Chennai where a family will live in.