Overview
Z-Wave, in practical terms.
Z-Wave is the protocol you reach for when the building is the problem. It runs at 865–867 MHz on the Indian band rather than the crowded 2.4 GHz everything else uses, which means it travels through brick and RCC noticeably better and never contends with your Wi-Fi. In a compact flat that rarely matters. In a duplex, a villa, or anywhere with thick internal walls, it can be the difference between a network that works and one that doesn't.
The trade-off is supply. Z-Wave device choice in India is thin compared with Zigbee and skewed towards locks and sensors, with little in Indian modular switch form factors, and devices cost more. One thing to get right before you buy: Z-Wave hardware is region-locked by frequency, so devices sold for the US or EU will not pair with an Indian hub. See Z-Wave vs Zigbee for the full comparison.
