The findings, released after four months of monitoring from September to December 2025, were based on satellite imagery, drone surveillance and field inspections conducted by the agency under the Ministry of Agriculture and Environment.
More than 100 active urban development projects, large construction sites and material dumping areas were flagged as potential sources of dust pollution.
The department also identified 14 craft villages posing air pollution risks, including Ha Thai, Da Sy, Ngu Xa, Bat Trang, Minh Khai, La Phu, Cat Que, Thanh Thuy, Van Canh, Son Dong, Phu Vinh, Gie Thuong, Tan Trieu and Trieu Khuc.
Within the Ring Road 4 boundary toward central Hanoi, authorities recorded 68 large construction sites currently under development.
Using Hoan Kiem Lake as the reference point, at least seven major projects lie within a five-kilometre radius, while no fewer than 35 large construction sites are operating within 10 kilometres of the lake, the department said.