Seven panda cubs born this year in Chengdu Research Base of Giant Panda Breeding in Sichuan province made their public debut on Tuesday.

It is the base’s tradition to show off newborn cubs before the National Day holiday, which runs from October 1 to 7 each year, and allow visitors to see the cubs until the holiday is over.

Unlike previous years, 2019 has witnessed the birth of the world's heaviest panda pair as well as the world’s lightest panda.

Female cub Cheng Lang weighed only 42.8 grams when she was born on June 11. As the world's lightest panda, Cheng Lang had the weight of an average chicken egg.

Panda cubs usually weigh around 150 grams, according to the base's chief Zhang Zhihe.

As it is demanding to raise particularly light cubs, the base has established a panel of experts proficient in nursing cubs to attend to Cheng Lang.

Cheng Lang is healthy and now weighs more than 5 kilograms, Zhang said.