Short answers, pulled from the story.
South Asia has a population of approximately 2.04 billion people, making it the most populous and most densely populated geographical region in the world. It contains roughly one-quarter of the world's total population.
The commonly recognized modern states of South Asia are Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka. Afghanistan is also often included, though it may alternatively be classified as part of Central Asia. The South Asian Association for Regional Cooperation (SAARC) lists all eight of these nations as members.
SAARC was established in Dhaka in December 1985, initially with seven member countries. Afghanistan was admitted as the eighth member in 2007.
The Indus Valley Civilisation was the first major civilisation in South Asia, spreading and flourishing in the northwestern part of the region from around 3300 to 1300 BCE across present-day Pakistan, North India, and Afghanistan. Its Mature Harappan period, from 2600 to 1900 BCE, produced a sophisticated and technologically advanced urban culture.
The 1947 Partition divided the British Indian Empire into a Hindu-majority Dominion of India and a Muslim-majority Dominion of Pakistan, resulting in large-scale loss of life and an unprecedented migration. It created lasting hostility between India and Pakistan, contributing to multiple wars, disputed territories including Kashmir, and the eventual formation of Bangladesh after the 1971 Bangladesh Liberation War.
Up to two-thirds of glacier ice in the Hindu Kush region may melt by 2100 under high warming scenarios, threatening water supplies for over 220 million people. Sea level rise in Bangladesh is projected to displace 0.9-2.1 million people by 2050, and under the high-emission scenario, 40 million South Asians may be driven to internal migration by 2050 due to climate change.