According to a Brooking’s report, India could overtake US to become the second largest middle-class market by 2022.

In addition, India probably overtook Japan in 2016.

Also, 90% of the entrants into the global middle class will be in Asia i.e. 380 mn Indians, 350 mn Chinese, and 210 mn other Asians. The rapid expansion in the middle-class is a result of high contribution to the world population.

For more: https://www.brookings.edu/wp-content/uploads/2017/02/global_20170228_global-middle-class.pdf