These are the highest rated smartwatches under Rs. 5,000 that can track your SpO2 blood oxygen levels. Although these smartwatches are not meant as medical devices, they can help you be alert to potential risks, and to know when to meet a doctor.

source https://gadgets.ndtv.com/wearables/features/track-blood-oxygen-spo2-affordable-smartwatches-under-5000-2422770#rss-gadgets-all