 Ammonium nitrate-based explosives were used in the Sterling Hall bombing in Madison, Wisconsin, 1970, the Oklahoma City bombing in 1995, the 2011 Delhi bombings, the 2011 bombing in Oslo, and the 2013 Hyderabad blasts.In November 2009, a ban on ammonium sulfate, ammonium nitrate, and calcium ammonium nitrate fertilizers was imposed in the former Malakand Division – comprising the Upper Dir, Lower Dir, Swat, Chitral, and Malakand districts of the North West Frontier Province (NWFP) of Pakistan – by the NWFP government, following reports that those chemicals were used by militants to make explosives.Due to these bans, "Potassium chlorate – the stuff that makes matches catch fire – has surpassed fertilizer as the explosive of choice for insurgents."