Mexico's environmental protection agency has issued an "urgent" call for local authorities to stop sewage and waste discharges into the Yucatán Peninsula's coastal, fresh-water lake of Bacalar.
The agency says state and municipal authorities should enforce sanitary and building codes and build water treatment facilities to stop discharges into the lake.
Bacalar is often known as the "Lagoon of Seven Colors" because of its crystalline, turquoise-hued waters. It is located on the southern end of the Caribbean coast, inland from the resort of Mahahual.
While still picturesque, the lake has suffered from increasing development in recent years and from what the agency describes as inadequate sewage infrastructure, open-air garbage dumps and unregulated construction.
The municipal government of Bacalar and state government of Quintana Roo had no immediate comment.