Primary school students pay tribute to martyrs at a cemetery in Huaying City, southwest China's Sichuan Province, April 1, 2021. The Tomb-sweeping Day, also known as Qingming Festival, which falls on April 4 this year, is a Chinese festival when people pay tribute to the dead and worship their ancestors by visiting tombs and making offerings. (Photo by Zhou Songlin/Xinhua)

Primary school students pay tribute to martyrs at a cemetery in Huaying City, southwest China's Sichuan Province, April 1, 2021. The Tomb-sweeping Day, also known as Qingming Festival, which falls on April 4 this year, is a Chinese festival when people pay tribute to the dead and worship their ancestors by visiting tombs and making offerings. (Photo by Zhou Songlin/Xinhua)

Students offer flowers at a cemetery for martyrs in Huaibei, east China's Anhui Province, April 1, 2021. The Tomb-sweeping Day, also known as Qingming Festival, which falls on April 4 this year, is a Chinese festival when people pay tribute to the dead and worship their ancestors by visiting tombs and making offerings. (Photo by Wan Shanchao/Xinhua)

Students clean tombstone at a cemetery for martyrs in Huaibei, east China's Anhui Province, April 1, 2021. The Tomb-sweeping Day, also known as Qingming Festival, which falls on April 4 this year, is a Chinese festival when people pay tribute to the dead and worship their ancestors by visiting tombs and making offerings. (Photo by Wan Shanchao/Xinhua)

Students offer flowers at a cemetery for martyrs in Huaibei, east China's Anhui Province, April 1, 2021. The Tomb-sweeping Day, also known as Qingming Festival, which falls on April 4 this year, is a Chinese festival when people pay tribute to the dead and worship their ancestors by visiting tombs and making offerings. (Photo by Wan Shanchao/Xinhua)