According to NATO press releases,[1] the bombing targeted oil refineries, roads, bridges, and telecommunications relay stations, facilities which had military uses.
[1] One such attack where NATO was accused of this was the bombing of the Ministry of Education in Novi Sad, premises which administered social welfare programmes.
A United Nations study (the BTF ‘Industrial Sites’ and ‘Danube’ missions) found that there were serious environmental issues, "requiring immediate action", some of which resulted from the bombing.
[4] The bombing of Novi Sad's refinery caused fires which burned 50,000 tons of crude oil, sending toxins and carcinogens into the air and contaminating groundwater.
[5] The clearing of the debris was important not only for Novi Sad, but for European states (such as Hungary and Romania) who were economically impacted by the blockade of river traffic to the Black Sea caused by the bombing.
In response to NATO's justification of actions, the Movement for the Advancement of International Criminal Law (MAICL) argued[2] that the civilian deaths caused were clearly disproportionate to the military benefits.