Broadband China Policy can alleviate city-level carbon inequality in China

doi:10.1016/j.regsus.2026.100349

Abstract

Abstract:

Understanding the role of digital infrastructure development in shaping carbon inequality (CI) is critical for promoting environmental equity in the digital era. While the digital infrastructure has expanded rapidly in China, its environmental implications remain ambiguous. This study investigated the impact of the Broadband China Policy (BCP) on city-level CI using a multi-period difference-in-differences (DID) approach with data from 2005 to 2022. Results showed that the implementation of the BCP led to a 7.2% average reduction in CI. This effect operated through two key mechanisms: industrial structure upgrading and technological innovation. While cities in the eastern region reduced CI mainly through upgrading from carbon-intensive secondary industries to less carbon-intensive tertiary sectors, cities in the non-eastern region benefited from enhanced technological innovation. These region-specific pathways underscore the adaptive potential of digital infrastructure in fostering inclusive green development. These findings highlight the role of digitalization as a transformative platform for environmental equity, offering theoretical and policy-relevant insights for designing targeted, region-sensitive strategies that integrate digital and low-carbon transitions.

Key words: Broadband China Policy (BCP), Carbon inequality (CI), Carbon emissions, Industrial structure upgrading, Technological innovation, Difference-in-differences (DID), Digital infrastructure development

DU Mengbing, ZHANG Caijing, QIU Ning, ZHANG Zhe, LI Wen, SHAN Wanyue, ZHANG Li. Broadband China Policy can alleviate city-level carbon inequality in China[J]. Regional Sustainability, 2026, 7(3): 100349.

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Category	Variable	Measurement	n	Mean	Standard deviation
Dependent variable	CI	Carbon inequality	5706	0.0014	0.0015
Independent variable	BCP	Whether the city is a BCP pilot city in the corresponding year: 1=yes; 0=no	5706	0.1521	0.3592
Control variable	GDP	Real GDP per capita (10,000 CNY/capita)	5706	3.6324	2.6015
	FE	The ratio of local general public budget revenue to GDP	5706	0.2842	0.2284
	PD	The ratio of permanent population to built-up area (10,000 persons/km²)	5706	5.0676	3.3930
	BA	The ratio of internet broadband access users to permanent population	5706	0.1508	0.0942
	MPP	The ratio of mobile phone users to permanent population	5706	0.9559	0.3734
Mediating variable	ISU	The ratio of the tertiary industry output to the secondary industry output	5706	1.0416	0.6493
Mediating variable	TIL	The number of patents per 10,000 people (patents/10,000 persons)	4592	9.3906	17.6442

Variable	lnCI (without control variables)	lnCI (with control variables)
BCP	-0.068^*** (0.0090)	-0.072^*** (0.0100)
Constant term	-6.685^***(0.0030)	-6.685^*** (0.0030)
Year fixed effect	Yes	Yes
City fixed effect	Yes	Yes
Adjusted R²	0.861	0.864
n	5706	5706

Variable	ISU	TIL
BCP	0.056^*** (0.0150)	3.514^*** (0.5760)
Constant term	1.027^*** (0.0040)	8.897^*** (0.1400)
Control variables	Yes	Yes
Year fixed effect	Yes	Yes
City fixed effect	Yes	Yes
Adjusted R²	0.750	0.823
n	5706	4592

Variable	Eastern region	Non-eastern region
BCP	-0.052^*** (0.0150)	-0.085^*** (0.0130)
Constant term	-6.796^*** (0.0040)	-6.641^*** (0.0030)
Control variables	Yes	Yes
Year fixed effect	Yes	Yes
City fixed effect	Yes	Yes
Adjusted R²	0.761	0.885
n	1584	4122

Variable	ISU		TIL
Variable	Eastern region	Non-eastern region	Eastern region	Non-eastern region
BCP	0.172^*** (0.0230)	0.014 (0.0180)	1.933 (1.4230)	3.700^*** (0.3930)
Constant term	1.029^*** (0.0070)	1.025^*** (0.0050)	18.788^*** (0.3580)	4.675^*** (0.0810)
Control variables	Yes	Yes	Yes	Yes
Year fixed effect	Yes	Yes	Yes	Yes
City fixed effect	Yes	Yes	Yes	Yes
Adjusted R²	0.899	0.777	0.857	0.759
Observations	1548	4104	1392	3200