This kind of talaq is valid.
The latest judgment by supreme court with regard to triple talaq says:
Triple talaq — or the practice whereby a Muslim husband pronounces talaq (divorce) three times to end a marriage — has two variations. One variation is to pronounce talaq three times in one sitting, either verbally or through various written media such as phone call, letter, WhatsApp, Skype, SMS and the likes. The other is to pronounce a talaq each over three months.
The triple talak (instant) hass been unconstitutional by 3:2 majority verdict by supreme court.
However, it seems the practice of triple talaq was declared as unconstitutional by a 3:2 majority of the court. It was the instant triple talaq which was at the centre of countrywide debate due to its arbitrary use by Muslim husbands.
This means the Muslim husband will continue to have his Sharia-based right to unilaterally divorce a wife.
The unilateral divorce by a Muslim husband happens because Muslim husbands are not permitted to go to court to effect divorce — and also because the right of divorce in Islam belongs to the husband, not to the wife. Accordingly, a Muslim wife in India can seek, not give, divorce either through a court or through Islamic clerics.