Sri Lankan here. We've had this type of ceramic filter here for at least 35 years: https://cdn.shopify.com/s/files/1/0182/4859/7582/files/Ultra...
https://en.wikipedia.org/wiki/Ceramic_water_filter
In the Sri Lankan context filters are more important than ever, but I think activated carbon ones? Water is (heavily, I think!) chlorinated but pollution is pretty bad.