column,description
rank_most_improved,1 = largest fall in PM2.5 (blank for cities not ranked)
city,City name (WHO settlement; nearby WHO entries within 20 km merged into the largest)
country,Country as named in the WHO database
iso3,ISO 3166-1 alpha-3 code
population,"Population used for the 300,000 filter: WHO database figure or GeoNames (cities15000) place matched by name within 20 km, whichever is larger"
trend_pct_per_year,"Fitted trend: slope of log(annual PM2.5) on year, expressed as % per year; median across merged entries"
change_over_decade_pct,trend_pct_per_year compounded over 10 years
pm25_first3yr_mean,Mean annual PM2.5 (µg/m³) over the first three qualifying years
pm25_last3yr_mean,Mean annual PM2.5 (µg/m³) over the last three qualifying years
first_year,First qualifying year (2013 to 2016 required)
last_year,Last qualifying year (2021 to 2024 required)
years_with_data,"Number of qualifying years (at least 6, spanning at least 7 years)"
who_settlements_merged,Number of WHO database entries merged into this city
list,"""10 most improved"" or ""10 got worse"" if shown in the video (at most 4 cities per country per list)"
who_entries,WHO database city entries used
excluded,Reason a city is listed but not ranked