Previously, there were 29 states. After the removal or abolition of Article 370, there are 28 states, because the state of Jammu & Kashmir is divided into two union territories – Jammu & Kashmir and Ladakh. 

Further Reading :

• Former Special Status Of Jammu And Kashmir
• J&K: One Year Since Revocation of Special Status: RSTV- Big Picture

To read more about Article 370, check the linked article.