Before revision:  Regional variations in CO_2 emissions are significant, with a decrease in China (-9.3\% ) , US (-3.0 \%), Europe ( EU-27 & UK)(-3.3\%) and India (-2.4\%) , respectively. The decline of short-lived gaseous pollutants, such as NO_2 concentration observed by Satellites (-25.73\%for China, -4.76\%for US) and ground observations (-23\%for China)is consistent with the estimates based on energy activity (-23.94\% for China, -3.52\% for US), but the decline is not seen in satellite assessments of aerosol optical depth (AOD) or dry column CO_2 (XCO_2). With fast recovery and partial re-opening of national economies, our findings suggest that total annual emissions may drop far less than previously estimated (e.g. , by 25\%for China and more than 5\%for the whole world) . However, the longer-term effects on CO_2 emissions are unknown and should be carefully monitored using multiple measures .
After revision:  Regional variations in CO_2 emissions are significant, with a decrease in China (-9.3\% ) , US (-3.0 \%), Europe ( EU-27 & UK)(-3.3\%) and India (-2.4\%) , the U.S. (4.5\%) and Europe (5.4\%) over the first quarter, suggesting that carbon-intensive activities have been disproportionally impacted .