This is probably Hooker’s onion, Allium hookeri, a species which is known to be cultivated in home gardens in the eastern Himalayas andother countries in South East Asia (confirmed by Allium expert Reinhard Fritsch at Gatersleben). This plant was found on a market in Aizawl, Mizoram, Eastern India by Paul Barney. Paul sells this form under the name Allium hookeri “Zorami”. It gets a mention in my book, although the cultivar name isn’t mentioned! It is growing slowly in my garden. The pictures are taken during a visit to Paul’s nursery Edulis near to Pangbourne in the Thames Valley, UK.
The location of Aizawl where Paul found this onion on a market