Along with committees and caucuses, ACT UP New York relied heavily on "affinity groups". These groups often had no formal structure, but were centered on specific advocacy issues and personal connections, often within larger committees. Affinity groups supported overall solidarity in larger, more complex political actions through the mutual support provided to members of the group. Affinity groups often organized to perform smaller actions within the scope of a larger political action, such as the "Day of Desperation", when the Needle Exchange group presented NY City Health Department officials with thousands of used syringes they had collected through their exchange (contained in water cooler bottles).