The Laws state that, throughout an innings, "the ball shall be bowled from each end alternately in overs of 6 balls". The name "over" came about because the umpire calls "Over!" when six balls have been bowled. At this point, another bowler is deployed at the other end, and the fielding side changes ends while the batsmen do not. A bowler cannot bowl two successive overs, although a bowler can (and usually does) bowl alternate overs, from the same end, for several overs which are termed a "spell". The batsmen do not change ends at the end of the over, and so the one who was non-striker is now the striker and vice-versa. The umpires also change positions so that the one who was at "square leg" now stands behind the wicket at the non-striker's end and vice-versa.
If a fielder is injured or becomes ill during a match, a substitute is allowed to field instead of him, but the substitute cannot bowl or act as a captain. The substitute leaves the field when the injured player is fit to return. The Laws of Cricket were updated in 2017 to allow substitutes to act as wicket-keepers, a situation that first occurred when Mumbai Indians' wicket-keeper Ishan Kishan was injured in a match on 18 April 2018.
During the 1980s, India developed a more attack-minded batting line-up with stroke makers such as the wristy Mohammed Azharuddin, Dilip Vengsarkar and all-rounders Kapil Dev and Ravi Shastri. India won the Cricket World Cup in 1983, defeating the favourites and the two-time defending champions West Indies in the final at Lords, owing to a strong bowling performance. In spite of this, the team performed poorly in the Test arena, including 28 consecutive Test matches without a victory. In 1984, India won the Asia Cup and in 1985, won the World Championship of Cricket in Australia. Apart from this, India remained a weak team outside the Indian subcontinent. India's Test series victory in 1986 against England remained the last Test series win by India outside the subcontinent for the next 19 years. The 1980s saw Gavaskar and Kapil Dev (India's best all-rounder to date) at the pinnacle of their careers. Gavaskar made a Test record 34 centuries as he became the first man to reach the 10,000 run mark. Kapil Dev later became the highest wicket-taker in Test cricket with 434 wickets. The period was also marked by an unstable leadership, with Gavaskar and Kapil exchanging the captaincy several times.
Eden Gardens in Kolkata has hosted the most Tests, and also has the second-largest seating capacity of any cricket stadium in the world, being capable of holding more than 66,000 spectators. Founded in 1864, it is one of the most historical stadiums in India, having hosted numerous historical and controversial matches. Other major stadiums in India include the Feroz Shah Kotla Ground, which was established in 1883 and hosted memorable matches including Anil Kumble's ten wickets in an innings haul against Pakistan. For the last two years, the ground has been undergoing renovation.