Pollution has caused some positive impacts unintentionally. Some harmful particles produced from burning waste, smoking or mixture of soots such as  Particulate Matter (PM 10 and PM 2.5) have decreased the heat coming from the sun instead of trapping it inside the atmosphere which has let the greenhouse gases warm the atmosphere to around 1.1°C instead of 1.5 °C. 

You can read more through  https://www.ucsusa.org/resources/what-solar-geoengineering