As of today, e-tourist visas are currently suspended. However, the government offers the possibility for foreigners to come for an Ayurveda cure with a medical visa which is easily obtainable online: https://indianvisaonline.gov.in/evisa/tvoa.html.
Before applying, you will need to consult with your Ayurvedic doctor at Nattika who will then write you a medical invitation letter. This letter will be necessary during the visa procedure. We advise you to apply at least two weeks before your arrival date.