People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Zhang Yuwei)

People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Zhang Yuwei)

People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Zhang Yuwei)

People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Zhang Yuwei)

People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Qin Qing)

People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Qin Qing)

People fly Kongming lanterns, a kind of small hot-air paper balloon, by the Lancang River in Jinghong City, southwest China's Yunnan Province, April 13, 2019, to celebrate the New Year of the calendar of the Dai ethnic group. (Xinhua/Qin Qing)