India's Prime Minister Narendra Modi has [asked / asking] world leaders to start a U.N. International Yoga Day. He was [speaking / spoken] at the U.N. General Assembly in New York. It was his [very / really] first speech at the 193-member General Assembly. He spoke about the [beneficial / benefits] of yoga, saying it was good for the [mind / mindless] and body, and could also help climate change. He said yoga [provide / provides] harmony between humans and nature, and is "an [invaluable / valuable] gift" from India's 5,000-year-old culture. Modi said: "It is not about exercise, [however / but] to discover the sense of [oneness / once] with yourself, the world and the nature." He added: "By changing our lifestyle and creating consciousness, it can help us deal [with / in] climate change." Many doctors and people [on / in] the medical community say yoga is a good way to [live / stay] physically and mentally healthy. Yoga makes you focus [in / on] exercise, breathing and meditation. A lot of research [say / says] it can help people with heart disease, high [bloody / blood] pressure and lower back pain. Studies also say yoga can improve our [moody / mood] , reduce stress and make us sleep [better / good] . However, there is also research that says people need to [be / do] careful when doing yoga. Wikipedia says: "An [extensive / extensively] survey of yoga practitioners in Australia showed that about 20 per cent had [suffered / suffering] some physical injury while practicing yoga." A World Yoga Day already exists. It was started by the world-yoga-day.org website in 2007.