Indian students smear coloured powder during an event to celebrate the Hindu festival of Holi in Kolkata on February 26, 2018. Holi, the popular Hindu spring festival of colours is observed in India at the end of the winter season on the last full moon of the lunar month, and will be celebrated on March 1 this year. (Photo by Dibyangshu Sarkar/AFP Photo)

People cross Flagstaff Hill as the snow starts to fall, in Schenley Park, on their way to the Carnegie Mellon University campus, Tuesday, March 20, 2018, in the Oakland section of Pittsburgh. Yet another powerful storm bore down on the Northeast on Tuesday, with wind-whipped snow falling in parts of Pennsylvania and New Jersey as people grumbled and complained about a first day of spring that looked an awful lot like the last weeks of winter. (Photo by Darrell Sapp/Pittsburgh Post-Gazette via AP Photo)

Lawmakers from the main opposition Republican People's Party (CHP) and ruling AK Party (R) scuffle during a debate on a legislation to boost police powers, at the Turkish Parliament in Ankara, Turkey, February 19, 2015. (Photo by Reuters/Stringer)

People carry lychee for sale on a motorbike on a street in Luc Ngan, Bac Giang province, Vietnam, 22 June 2016. Lychee output in Bac Giang province is expected to reach 130,000 tonnes this year. China is still Vietnam's main lychee export market so far, buying around 60 percent of the annual crop, according to official reports. (Photo by Luong Thai Linh/EPA)

A farmer harvests tobacco leaves at a plantation in the valley of Vinales, in the western Cuban province of Pinar del Rio, January 27, 2015. (Photo by Pilar Olivares/Reuters)

People look at huge waves crashing on the San Esteban de Pravia seafront, northern Spanish region of Asturias February 8, 2016. (Photo by Eloy Alonso/Reuters)

A partial solar eclipse is seen as a labourer works at a construction site in Phnom Penh, Cambodia, March 9, 2016. (Photo by Samrang Pring/Reuters)

Women comfort each other as they mourn over the death of a family member who was killed in a bomb blast, at a local hospital in Lahore, Pakistan, Sunday, March, 27, 2016. A bomb blast in a park in the eastern Pakistani city of Lahore has killed tens of people and wounded scores, a health official said. (Photo by K.M. Chuadary/AP Photo)