While other metropolises in India had already redefined their respective metropolitan regions to include much larger areas, CMA had not been altered since it was first defined in 1974.

[10][11] As per the act, the government is required to allow reasonable opportunity (two months) for inhabitants, local authorities and institutions in the area to comment upon or object to such an expansion proposals and few objections were received including a public interest litigation filed at the Madras High Court in March 2018.

[14] The metropolitan area consists of four municipal corporations (Greater Chennai, Tambaram, Avadi, Kancheepuram), 12 municipalities (Arakkonam, Mangadu, Kundrathur, Poonamallee, Thiruverkadu, Thiruninravur, Tiruvallur, Tiruttani, Maraimalai Nagar, Chengalpattu, Ponneri, Guduvancheri) and other smaller panchayats spread across the districts of Chennai, Thiruvallur, Kancheepuram, Chengalpattu and Ranipet.

[22] Chennai has a broad industrial base in the automobile, computer, technology, hardware manufacturing and healthcare sectors.

As of 2012[update], the city is India's second-largest exporter of information technology (IT) and business process outsourcing (BPO) services.

[23][24] A major part of India's automobile industry is located in and around the city thus earning it the nickname "Detroit of Asia".