NEW DELHI (AP) — Schools have reopened in the Indian capital with toxic air level coming down by more than half since authorities declared a health emergency last Friday.

With strong winds blowing away pollutants, the air quality index at the U.S. Embassy in New Delhi read 155 on Wednesday as compared to 500 over the weekend that was 10 times the recommended WHO level.

Air pollution in New Delhi peaks around Nov. 1 due to smog from festival fireworks and smoke from the burning of stubbles in agricultural fields.

But the battle is not over as authorities tackle a large amount of toxic foam floating in the Yamuna River, caused partly by high ammonia levels emanating from industrial pollutants. A weekend Hindu festival saw thousands of devotees offering prayers standing in the foam.