Volcanic Eruption Emergency Response Project The Hunga Tonga-Hunga Ha'apai undersea volcano, located about 65 kilometers north of the Kingdom of Tonga's capital Nuku'alofa, erupted on 15 January 2022. The eruption produced an ash cloud that rose 30 kilometers (km) in altitude, launched an estimated 1 cubic kilometer of material into the atmosphere, and triggered a tsunami which resulted in inundation in Tonga and affected other countries, with waves recorded as far away as Japan, Peru, and the United States.

An estimated 85,000 people (84% of the population) were directly affected. Tsunami waves affected the west coast of Tongatapu (the main island), the island of 'Eua, and the Ha'apai group of islands, travelling up to 200 meters inland. The Government of Tonga reported three confirmed fatalities. The islands of 'Atata, Mango, Fonoifua, and Nomuka were the worst affected with all but the largest buildings destroyed, leaving widespread debris. The populations of these islands were evacuated to other islands where evacuation shelters were established. Government reported 293 houses across Tonga were damaged or destroyed and over 1,500 persons were displaced. Ashfall, measuring between 5-10 centimeters thick on Tongatapu, impacted all island groups, resulting in defoliated trees, buried crops, damaged public infrastructure and houses, and contaminated water supplies. These impacts led to food and water insecurity.

The government declared a state of emergency commencing 16 January 2022, pursuant to section 32 of the Emergency Management Act. The National Emergency Management Office coordinated and monitored relief efforts by government agencies, and local and international nongovernmental organizations. Immediate relief efforts focused on the provision of food, non-food items (including water containers, hygiene kits, and household items), shelter, and clean-up of the ashfall. The restoration of critical infrastructure and essential services, particularly international and domestic communications, were also prioritized. Restoration efforts were challenging due to the nationwide state of emergency in place for the coronavirus disease (COVID-19) Humanitarian and development partner support was critical to help the government meet immediate needs of the impacted population.

The government requested support from ADB under the Asia Pacific Disaster Response Fund (APDRF) on 25 January 2022. The UN Resident Coordinator, on 27 January 2022, confirmed the need for APDRF assistance and acknowledged that a contribution by ADB to support the government to meet immediate humanitarian needs, in partnership with the international humanitarian community, would be appreciated. Based on identified needs, a grant of $500,000.00 from the APDRF was approved to help fund expenses necessary to restore life-sustaining services, including but not limited to: (i) provision of medical kits, food, and bottled drinking water; (ii) purchase of water purification and sanitation systems; (iii) provision of transitional shelter; (iv) provision of personal hygiene kits; (v) site clearing; and (vi) safe disposal of useless rubble. to help fund expenses necessary to restore life-sustaining services, including but not limited to: (i) provision of medical kits, food, and bottled drinking water; (ii) purchase of water purification and sanitation systems; (iii) provision of transitional shelter; (iv) provision of personal hygiene kits; (v) site clearing; and (vi) safe disposal of useless rubble.