Francisco Mateus da Silva, 67, spent an hour walking across sandbanks and dry riverbeds where he lives in the Amazon to fetch food and water amid the worst drought on record in the region, which has paralyzed river transportation.

The environmental risks of dredging include ecosystem disruption, increased erosion, water contamination, and harm to aquatic species such as manatees and river dolphins.

Satellites detected 41,463 fire hot spots in Brazil’s Amazon in September, the largest number since 2010, according to data from the National Institute for Space Research (Inpe).