The name of the act and the process that created and divided India, Pakistan and Bangladesh is the 'Partition of India'. It happened in 1947, when the till then one country, was divided in three parts and gave birth to the today's Republic of India, Islamic Republic of Pakistan and People's Republic of Bangladesh.
I think water and food is something that's encouraged people to settle where I live.
Straw and mud or clay, or otherwise called adobe (uh-dough-bee)
If the region rises in population it will most likely cause a bigger scarcity in water, which may lead to a drought. A drought can ruin crops and leave land dry.
