"You will never be alone. Your family will love you forever," reads an engraving on a tombstone in the northern suburbs of Beijing.

A 70-year-old woman surnamed Li sweeps the tomb, but it is not dedicated to a relative; it is the final resting place of her dog, which died five years ago.

The tomb is surrounded by plastic flowers and snacks, and a photograph of the dog is pasted on the tombstone. Its name was Nini, and it was the family dog for 18 years.