Explanation:

Uttar Pradesh is the most populous state in India with estimated population of 23.79 crores in 2019. Uttar Pradesh accounts for 17.35% of the total country population. Bihar has overtaken Maharashtra as the second largest state by population with close to 125 million people living here. 

India is a union of 28 states and 8 union territories. As of 2011, with an estimated population of 1.2 billion, India is the world's second most populous country after the People's Republic of China. India occupies 2.4% of the world's area and is home to 17.5% of the world's population. The Indo-Gangetic plains have one of the world's biggest stretches of fertile flat-deep alluvium and are among the most densely populated areas of the world. The eastern and western coastal regions of Deccan Plateau are also densely populated regions of India.