Dongguan and the Hapai region of Tonga formally became sister cities in July 2019.

The Ha'apai group is comprised of 62 islands. The islands include barrier reefs, shallow lagoons, coral shoals, and even active volcanoes, but most are small low-lying coral atolls. There are east-west passes between islands which somewhat separate islands into groups. The eastern islands are a series of barrier islands running north-south, and the western islands are individual islands. Of the 62 islands in the Ha'apai group, only 17 are inhabited. On those 17 islands, there are approximately 8,000 people settled in 30 villages. Income for these islanders is from agriculture and/or fishing. However, as in much of Tonga, the largest source of income is remittances from family members living abroad.

There is limited infrastructure in this island group. Only the four largest islands have electricity. The other islands are without electricity, running water, or telephones. And even the largest islands with electricity do not have television.