This paper’s RD design exploits the discrete increase in the
availability of free indoor heating as one crosses the Huai River
line (with no availability to the south and, in principle, complete
availability north of the line). Specifically, we separately test
whether the Huai River policy caused a discontinuous change in
TSPs at the river and a discontinuous change in life expectancy.
The respective necessary assumptions are that any unobserved
determinants of TSPs or mortality change smoothly as they
cross the river. If the relevant assumption is valid, adjustment
for a sufficiently flexible polynomial in distance from the river
will remove all potential sources of bias and allow for causal
inference.