Many enviros have suspected for a while that the deregulation of electricity markets is bad for the environment. Now here’s some proof: Spending on energy efficiency programs by North American power companies — the biggest polluters on the continent — dropped by 42 percent between 1995 and 1999, largely because of deregulation. The findings were made public this week in a report by the Commission for Environmental Cooperation, a Montreal-based agency created under the North American Free Trade Agreement. The drop in spending, from $2.4 billion to $1.4 billion, led to increased air pollution in the U.S., Canada, and Mexico, affecting both human and environmental health. Janine Ferretti, executive director of the commission, said deregulation offers utilities fewer incentives to implement conservation measures. The report came just two days after President Bush announced that he would relax rules requiring utilities to install state-of-the-art pollution-control equipment when repairing or expanding power plants, a move that triggered a storm of protest from environmental groups.