When India started playing Test cricket, they did not have a genuine seam bowler, hence would open the bowling with a spinner and part-timers.
Today India have world class fast bowlers, but yet their success at home is based on spinners, not fast bowlers.
Now, in recent times spinners would open the bowling for India at home. The pitch dictates captain to employ spinners from the onset, and someone like Ravi Ashwin has done it very regularly. He opened the bowling in 41 inns (92 played) picking 161 wickets. His current spin partners Axar Patel has opened in 4 inns. Ravi Jadeja has opened in 6 inns.
The key reason being…the new ball has been very productive for spinners in India!.
Although interestingly this helped India win test matches at home, but has affected their overall batting performance!.
In the ongoing Border-Gavaskar Trophy the new ball (1st new ball, 2nd new ball) produced 32 wickets, of which 27 went to spinners…and India lost 18 wickets to new ball of which 16 went to Australian spinners.
Spinners picking regular wickets with new ball has been the ongoing trend in India.
Let us look at India's recent performance at home. They played England, New Zealand and Sri Lanka.
Team Batting performance a comparison against spin / new ball