Objectives To evaluate the profile of non-urgent patients triaged ‘green’, as part of a triage trial in the emergency department (ED) of a secondary care hospital in India. The secondary aim was to validate the triage trial with the South African Triage Score (SATS).Design Prospective cohort study.Setting A secondary care hospital in Mumbai, India.Participants Patients aged 18 years and above with a history of trauma defined as having any of the external causes of morbidity and mortality listed in block V01–Y36, chapter XX of the International Classification of Disease version 10 codebook, triaged green between July 2016 and November 2019.Primary and secondary outcome measures Outcome measures were mortality within 24 hours, 30 days and mistriage.Results We included 4135 trauma patients triaged green. The mean age of patients was 32.8 (±13.1) years, and 77% were males. The median (IQR) length of stay of admitted patients was 3 (13) days. Half the patients had a mild Injury Severity Score (3–8), with the majority of injuries being blunt (98%). Of the patients triaged green by clinicians, three-quarters (74%) were undertriaged on validating with SATS. On telephonic follow-up, two patients were reported dead whereas one died while admitted in hospital.Conclusions Our study highlights the need for implementation and evaluation of training in trauma triage systems that use physiological parameters, including pulse, systolic blood pressure and Glasgow Coma Scale, for the in-hospital first responders in the EDs.