View of a damaged bridge at the Iguacu Falls on June 12, 2014, in Foz do Iguacu, Brazil, following the overflowing of the Parana river. In neighbouring Paraguay flooding has forced the evacuation of about 150,000 people in Paraguay's capital city Asuncion, authorities said. (Photo by Norberto Duarte/AFP Photo)

Long-tailed mayflies (Palingenia longicauda) at Tisza river near Tiszainoka 135km (84 miles) southeast of Budapest, June 23, 2013. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during “Tiszaviragzas” or Tisza blooming season from late spring to early summer every year. (Photo by Laszlo Balogh/Reuters)

Bangladeshi railway police try to clear line, as thousands of Bangladeshi Muslims gather to board trains to return home after attending three-day Islamic Congregation on the banks of the River Turag in Tongi, 20 kilometers (13 miles) north of the capital Dhaka, Bangladesh, Sunday, January 26, 2014. (Photo by A. M. Ahad/AP Photo)

A devotee dressed as Hindu Lord Shiva waits to participate in a parade during “Kumbh Mela” or the Pitcher Festival in Trimbakeshwar, India, August 18, 2015. The Kumbh Mela takes place four times every 12 years at four different river bank locations in India. (Photo by Danish Siddiqui/Reuters)

A mother reacts as she pleads with police to allow her daughter to pass a checkpoint for cancer treatment after she arrived from Hubei province at the Jiujiang Yangtze River Bridge in Jiujiang, China, February 1, 2020. (Photo by Thomas Peter/Reuters)

Indigenous nurses from the Special Secretariat for Indigenous Health (Sesai) of the Arapiuns ethnic group and Tapuia ethnic groups perform a rapid COVID-19 test on Chief Domingos from the Arapium tribe on the banks of the lower Tapajos River in the municipality of Santarem in western Para on July 19, 2020. (Photo by Tarso Sarraf/AFP Photo)

An Indian boy sells flowers to Hindu devotees of Lord Shiva as they perform rituals after collecting water from the river Ganges during the holy month of Shravan, In Allahabad on July 22, 2019. Shravan is considered the holiest month in the Hindu calendar with many religious festivals and ceremonies. (Photo by Sanjay Kanojia/AFP Photo)

A girl catches a fish in the marshes of the southern district of Chibayish in Dhi Qar province, about 120 kilometres northwest of the southern city of Basra, on September 23, 2020. Iraq's southern marshes are blossoming thanks to a wave of ecotourists picnicking and paddling down their replenished river bends. (Photo by Hussein Faleh/AFP Photo)