Beijing is the capital city of China located in northern China. It has a population of over 20 million people representing 56 ethnic groups. The city has 16 urban districts and 2 rural counties. Beijing has a dry, continental climate with very cold, dry winters and hot, humid summers. The urban core consists of four central districts while the outer districts are more suburban in nature. Air pollution is a major environmental issue, with studies finding air quality making the city almost uninhabitable at times. The government is working to address this through initiatives like the China Beijing Environment Exchange.