Canadian Prime Minister Justin Trudeau has singled out the oil and gas industry as a target for toughened pollution policing in his campaign for reelection of his Liberal government in a Sept. 20 national vote.

“Let’s be realistic,” said Trudeau as he unveiled an environmental plank in the party platform at a weekend rally in Cambridge, a southwestern Ontario auto manufacturing and university community. “Over one-quarter of our emissions [of greenhouse gases] come from our oil and gas sector. We need the leadership of these industries to decarbonize our country.”

Election campaign additions to Liberal policy would require all participants in the oil and gas sector to make formal annual emissions reduction commitments beginning in 2025, and to deepen methane leakage and...