Indian passengers stand and hang onto a train as it departs from a station on the outskirts of New Delhi.Money Sharma | AFP | Getty ImagesThe world population reached 8 billion people on Tuesday, and India is expected to surpass China as the most populous country in the next year, according to projections from the United Nations.The global population has more than tripled since 1950 as mortality dropped and life expectancy increased, due in large part to better sanitation, access to clean drinking water, and the development of vaccines and antibiotics, along with improved nutrition.Between 1990 and 2019, human life expectancy at birth increased by almost nine years to age 72, according to the U.N. People in the poorest nations, however, died about seven years earlier than the global average due to high levels of child and maternal mor …
