March 20 marks the second International Day of Happiness. Tsinghua University has issued a happiness index. It looks at how people in China's sense of contentment relate to economic development, and measures what situations and factors could change this feeling.

According to a UN survey, China ranked 93 among 156 countries in terms of happiness in 2013. And that was an improvement on 2012, when it ranked 112.

"Industrialization and urbanization have brought great conveniences to our society, but also many social problems, especially psychological ones. According to the statistics of the World Health Organization, 200 thousand people die because of psychological problems each year in China," professor Peng Kaiping from Tsinghua University said.

The WHO also says across the globe, more than a million people die each year from suicide. And the number is on the rise. In recognition of this, the UN set March 20th as the International Day of Happiness in 2012, with a view to promote people's well-being.