Solving the 2021 DEBS grand challenge using Apache Flink

The DEBS Grand Challenge is an annual event in which different event-based systems compete to solve a real-world problem. For the year 2021, the challenge is computing information given air quality sensor data. Due to the pandemic many factories are forced to close down, and the aim is to find out the cities that have improved the most in air quality and cities that have achieved the longest sequence of good AQI values. This paper aims to solve the above challenges using Apache Flink, an open-source, unified stream-processing and batch-processing framework developed by the Apache Software Foundation.