Stock OSM tiles — default options

indiaBoundaryLayer() — carto's own colour and per-zoom width, at carto's own opacity: 0.5. Zoom out below z4 and the boundary disappears, because the basemap stops drawing national borders there too.

Filtered dark basemap — tileFilter

Same layer, same data. The tile pane is inverted in CSS, so the overlay is given the identical filter and its opacity defaults to 1 instead of 0.5. Without both, the border is either the wrong colour or invisible.

Suppressed + overlay — suppressedTileLayer (experimental)

The tiles are edited in a canvas to erase the LoC and LAC, then the boundary overlay adds India's claim — one line instead of two. Labels are untouched and stay as OSM rendered them, which is why this is not a route to the official depiction. Add ?debug to the URL to paint the mask instead of inpainting under it.