Rauner’s staff had earlier pushed for quick adoption of amendments to state rules that would have scrapped limits on the rate of pollution from Vistra’s eight coal plants in central and southern Illinois. The proposed changes, drafted with extensive input from the company’s Chicago-based attorneys, would have replaced the rate-based limits with annual caps on tons of sulfur dioxide and nitrogen oxide emitted by the fleet — a subtle but significant shift that could have stalled or reversed efforts to reduce Vistra’s contributions to smog, soot and acid rain.