M.C. Mehta v Union of India (Delhi Air Pollution Case)

• Delhi's air quality continued to deteriorate severely during specific periods, particularly during winter months
• Specific contributing factors, including construction dust, crop residue burning in neighbouring states, and firecracker use during festival periods, were identified
• The Graded Response Action Plan and related emergency measures had been established but faced ongoing implementation and enforcement challenges

1. Whether continuing judicial oversight is necessary to ensure the effective, actual implementation of established air quality emergency response frameworks, beyond their formal establishment.

• The Supreme Court continued its sustained engagement with Delhi's air pollution crisis, applying a continuing mandamus approach analogous to the earlier river pollution litigation
• The Court addressed specific implementation gaps, including inadequate enforcement of construction dust restrictions and the persistent challenge of crop residue burning in neighbouring states
• This sustained oversight reinforced that formal establishment of a regulatory framework, such as GRAP, does not by itself guarantee effective implementation across the numerous agencies and jurisdictions involved

Complex, multi-jurisdictional environmental emergencies, such as Delhi's air quality crisis spanning multiple states and agencies, require continuing judicial oversight beyond the formal establishment of a regulatory response framework, to address ongoing implementation gaps and enforcement failures as they emerge.