local pollutants = {
    ["pollution"] = 1,
    ["spores"] = 2,
    ["noise"] = 3,
    ["radiation"] = 4
}

for _, planet in pairs(data.raw["planet"]) do
    if planet.pollutant_type and pollutants[planet.pollutant_type] then
        planet.surface_properties = planet.surface_properties or {}
        planet.surface_properties["pollutant-type"] = pollutants[planet.pollutant_type]
    end
end