Participants climb over a wall at the “Tough Mudder” endurance event series in Arnsberg September 6, 2014. Competitors who took part in the endurance event saw themselves having to overcome various military style obstacles. (Photo by Ina Fassbender/Reuters)

Hindu women worship the Sun god Surya in the polluted waters of the river Yamuna during the Hindu religious festival of Chatt Puja in New Delhi October 30, 2014. Hindu women fast for the whole day for the betterment of their family and the society during the festival. (Photo by Ahmad Masood/Reuters)

28 year old Rupa has her hair shaven to donate to the Gods at the Thiruthani Murugan Temple November 10, 2016 in Thiruttani, India. Rupa donated her hair with the wish that her daughter's illness is cured. The process of shaving ones hair and donating it to the Gods is known as tonsuring. It is common for Hindu believers to tonsure their hair at a temple as a young child, and also to celebrate a wish coming true, such as the birth of a baby or the curing of an illness. The “temple hair”, as it's known, is then auctioned off to a processing plant and then sold as pricey wigs and weaves in the US, Europe and Africa. (Photo by Allison Joyce/Getty Images)

A citizen rides in smog on December 20, 2016 in Jinan, Shandong Province of China. Air quality index (AQI) readings exceeded 400 and some schools have suspended classes in Jinan. (Photo by VCG/VCG via Getty Images)

A labourer pulls a cart loaded with sacks of spices at a wholesale spice and chemical market in the old quarters of Delhi, India, December 19, 2016. Picture taken December 19, 2016. (Photo by Adnan Abidi/Reuters)

Festival goers having fun at the Balaton Sound music festival in Zamardi next to the Lake of Balaton, 110 km (68 miles) west of Budapest, July 6, 2017. (Photo by Zsolt Furesz)

A street vendor spreads vermilion powder used for worship during the Tihar festival, also called Diwali in Kathmandu, Nepal, November 9, 2015. Hindus all over Nepal are celebrating the Tihar festival during which they worship cows, which are considered a maternal figure, and other animals. Also known as the festival of lights, devotees also worship the goddess of wealth Laxmi by illuminating and decorating their homes using garlands, oil lamps, candles and colourful light bulbs. (Photo by Navesh Chitrakar/Reuters)

A woman carrying cabbage leaves on her head buys tomato at a market in Ahmedabad, India, November 9, 2015. India's villages face a sharp spike in food prices in 2016, as a second year of drought drives up the cost of ingredients such as sugar and milk, and poor transport infrastructure stops falling global prices from reaching rural areas. (Photo by Amit Dave/Reuters)