These two women just got out of the water and were walking on the beach in Madurai. Their swimming costumes (In India, swimming suits are commonly referred to as swimming costumes.) are their every day clothing. This was not an uncommon situation in the country.
During my very first trip to India, we went to a beach on a sweltering day in June. To my utter amazement, people were swimming in the ocean fully clothed. There was not a bikini or swimsuit in sight. In fact, other than me, there was only one other person wearing shorts on the entire, crowded beach.
During my 18 months living in India, I saw quite a few women swimming in the pool where I lived. The only time I saw what I would call a bathing suit was when Westerners were in the pool. The India women tended to wear long shorts and t-shirts while in the water.