What is Tapasya? What is concentration?

The following is an excerpt from a samvaad (dialogue) session with Acharya Prashant.

Question 1: What is ‘Tapasya‘ (austerity)? Why is ‘Tapasya‘ necessary?

Acharya Prashant (AP): In the cold areas of the country, it becomes important, especially in winters, to let the sunlight in. Quilts etc. are kept out in the open so that they receive the Sun treatment. The Sun must…