We test the effectiveness of payments for ecosystem services (PES) in reducing crop residue burning, which contributes significantly to India’s poor air quality. Standard PES contracts pay a monetary reward after verification that the participant has met a pro-environment condition (clearing agricultural fields without burning). We randomize paying a portion of the money up front and unconditionally to address liquidity constraints and farmer distrust, which may undermine the standard contract’s effectiveness. Despite providing a lower reward for compliance, contracts with partial upfront payment increase compliance by 10 percentage points, which is corroborated with satellite-based burning measurements. The cost per life saved using this strategy is $4400. In contrast, standard PES has no effect on burning; the payments made are entirely inframarginal.