The Aam Aadmi Mohalla Clinics of the Delhi government have received national and international attention for their unique public health service delivery design. From April 2016 to March 2017 they delivered over 31 lakh free outpatient consultations at an average cost of `94 per consultation. This paper provides first-hand information and insight into how the clinics were operationalised in terms of infrastructure, human resources, laboratory services, medicines, and technology. It analyses their utilisation, financing, strengths and challenges at the operational, administrative and political level, and discusses how, in low-income settings, urban health systems can be strengthened using this model to expand primary healthcare services.