India is the world's third-largest emitter of carbon dioxide and is developing rapidly. While India has pledged an emissions-intensity reduction as its contribution to the Paris Agreement, the country does not regularly report emissions statistics, making tracking progress difficult. Moreover, all estimates of India's emissions in global datasets represent its financial year, which is not aligned to the calendar year used by almost all other countries. Here I compile monthly energy and industrial activity data allowing for the estimation of India's CO2 emissions by month and calendar year with a short lag. Emissions show clear seasonal patterns, and the series allows for the investigation of short-lived but highly significant events, such as the near-record monsoon in 2019 and the COVID-19 crisis in 2020. Data are available at https://doi.org/10.5281/zenodo.3894394 (Andrew, 2020a).