A SMALL group of Pueblo Indians, living just south of Albuquerque, the largest city in New Mexico, may force city officials to spend a whopping US $250 million to clean up the Rio Grande, so they can be assured of water with the level of cleanliness needed for their religious rites. The Pueblos have invoked an 1987 amendment to the US Clean Water Act in their lawsuit, which could set a precedent for native American tribes throughout the country.

Pueblo leaders maintain the amendment allows them to set their own standards of water purity and these have been set much higher than the state government's standards. Meanwhile, Albuquerque officials have sued the US Environmental Protection Agency, which approves standards, seeking exemption.