Los Angeles has become the biggest U.S. city to pass green-building laws. Under the regulations announced Tuesday, new commercial and residential structures of more than 50,000 square feet will have to be LEED certified by the U.S. Green Building Council. The law also applies to major renovations. “We look toward the future through a greener lens,” says Mayor Antonio Villaraigosa, “after decades of poor policies that neglected environmental concerns.” Some critics say the L.A. standards lag in comparison to San Francisco, which is considering a proposal that would require LEED Silver certification for buildings of more than 25,000 square feet. Los Angeles city councilfolks counter that they expect to make L.A.’s standards stricter over time.