Backgrounder: "World No Tobacco Day"

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Play VideoCampaign to mark " World No Tobacco Day"

Since the 1950s, a number of studies have shown smoking is the primary cause of lung cancer.

In 1987, the World Health Organization proposed to set April 7th as World No Tobacco Day, aiming to increase public awareness of the dangers of smoking.The first World No Tobacco Day was observed the following year.

Since 1989, the World No Tobacco Day has been held on May 31st. Studies have also shown that smoking is the world's Number Two killer, following high-blood pressure.

The WHO warns that about half of smokers will eventually die of smoking-related diseases. And passive smoking harms the health of tens of thousands of non-smokers each year.