Anak Krakatoa is currently erupting in Indonesia, leading to poor air quality in nearby Singapore and Malaysia (on top of the existing Sumatran fires which already started the annual ‘haze’).

When Krakatoa erupted in 1883 it lasted for 5 whole months and dropped global temperature by as much as 1.2C / 2.2F

Anak Krakatoa means child of Krakatoa, as it emerged from the caldera formed by the 1883 eruption

https://climatecontroljournal.com/how-did-krakatoa-affect-the-climate-around-the.html