bigquery1.sql

  SELECT
      city, AVG(value) as avg_aqi, latitude, longitude
  FROM
      `bigquery-public-data.openaq.global_air_quality`
  WHERE
      pollutant = 'pm25'
      AND (city = 'Beijing' OR city = 'Shanghai')
      AND EXTRACT(YEAR FROM timestamp) BETWEEN 2017 AND 2021
  GROUP BY
      city, latitude, longitude