Public buildings to be constructed in Sao Paulo, Brazil's most populous state, with 40 million inhabitants, will have solar energy units to heat at least 30 percent of the hot water consumed. It is the first time that a state has adopted such a measure in this country of more than 188 million people. There are seven cities with similar regulations, including two state capitals — Belo Horizonte and Porto Alegre — both in the south.

The regulation was approved in November by the state Legislative Assembly and will affect schools, hospitals and government office buildings.

Sao Paulo's leadership is significant because of the state's relative weight nationally, and will serve as an example, Délcio Rodrigues, coordinator of the Solar Cities Initiative, told Tierramérica.

“The energy issue is regulated by the national government, and urbanization by the municipalities,” which limits the role of the state in those areas, he explained.