BEIJING, Dec. 31 -- China's Beijing-Tianjin-Hebei region continued to witness development progress in 2021, with open and green development serving as the main drivers, official data showed.

The Beijing-Tianjin-Hebei regional development index stood at 138.9 points in 2021, 7.7 points higher than the 2020 level, according to the National Bureau of Statistics (NBS).

Sub-readings of open development and green development led the overall index increase in the reporting period by posting significant gains of 19.9 and 8.5 points, respectively, said the NBS.

Advances in innovative development, green development, and coordinated development proved the main contributors to the index, scoring 153, 153, and 141.6 points, respectively, the bureau revealed.

Total goods exports and imports of the region jumped 35.5 percent year on year to 687.4 billion U.S. dollars in 2021, while foreign direct investment in the region, in actual use, went up 9.6 percent.

The region also enjoyed better air quality and a more sustainable energy mix in 2021. The average density of PM2.5 -- fine particulate matter that causes smog -- fell 15.6 percent compared to a year earlier. Renewable energy accounted for 8.8 percent of the region's total energy consumption, up 1.9 percentage points from 2020.

China in 2015 rolled out a plan for the coordinated development of Beijing, Tianjin, and Hebei. Progress has since been made in many fields including environmental protection, public services, and transport.