You can download Digital Elevation Model (DEM) From Earth Explorer - USGS, using this DEM Raster (cell size usually 30m) you can extract slope as a raster and then convert it into shapefile.


Singapore offers an API for pollution levels (among 13 other real-time APIs) try it in their docs page: https://data.gov.sg/dataset/psi or with curl curl -X GET "https://api.data.gov.sg/v1/environment/psi" -H "accept: application/json" or with the browser: https://api.data.gov.sg/v1/environment/psi (not sure if any of these 14 real-time APIs are ...

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