Rising Chinese pollution levels measured from space are showing a gradual but uneven industrial pickup after the economic slowdown caused by the nation’s fight to contain the deadly novel coronavirus. Though the measure of nitrogen dioxide in China’s atmosphere has risen nearly 50% from Feb. 17, it’s still roughly 20% below the equivalent period last year, according an analysis from the Helsinki-based Centre for Research on Energy and Clean Air, which used satellite data from NASA.

The data offers important clues to the health of the world’s second-largest economy. The country’s official manufacturing purchasing managers’ index plunged to a record low in February, underscoring the impact from the Covid-19 outbreak, which has pummeled both consumption and production.

Provincial-level data can offer insights into specific industries, which often cluster by region. In the northern province of Hebei, which is China’s top steel-making area, NO2 levels have risen above the equivalent period last year, suggesting a partial recovery.

Hebei

NO2 levels in China’s top steelmaking province are above last year’s In the manufacturing hub of Guangdong, a province that as of Wednesday had the most coronavirus infections after Hubei province where the disease began, pollution briefly outpaced levels in 2017 and 2019 before falling below by late February.