The ball is a hard leather-seamed spheroid, with a circumference of 22.9 centimetres (9.0 in). The ball has a "seam": six rows of stitches attaching the leather shell of the ball to the string and cork interior. The seam on a new ball is prominent and helps the bowler propel it in a less predictable manner. During matches, the quality of the ball deteriorates to a point where it is no longer usable; during the course of this deterioration, its behaviour in flight will change and can influence the outcome of the match. Players will, therefore, attempt to modify the ball's behaviour by modifying its physical properties. Polishing the ball and wetting it with sweat or saliva is legal, even when the polishing is deliberately done on one side only to increase the ball's swing through the air, but the acts of rubbing other substances into the ball, scratching the surface or picking at the seam are illegal ball tampering.
As illustrated above, the pitch is marked at each end with four white painted lines: a bowling crease, a popping crease and two return creases. The three stumps are aligned centrally on the bowling crease, which is eight feet eight inches long. The popping crease is drawn four feet in front of the bowling crease and parallel to it; although it is drawn as a twelve-foot line (six feet either side of the wicket), it is, in fact, unlimited in length. The return creases are drawn at right angles to the popping crease so that they intersect the ends of the bowling crease; each return crease is drawn as an eight-foot line, so that it extends four feet behind the bowling crease, but is also, in fact, unlimited in length.
The game on the field is regulated by the two umpires, one of whom stands behind the wicket at the bowler's end, the other in a position called "square leg" which is about 15–20 metres away from the batsman on strike and in line with the popping crease on which he is taking guard. The umpires have several responsibilities including adjudication on whether a ball has been correctly bowled (i.e., not a no-ball or a wide); when a run is scored; whether a batsman is out (the fielding side must first appeal to the umpire, usually with the phrase "How's that?" or "Owzat?"); when intervals start and end; and the suitability of the pitch, field and weather for playing the game. The umpires are authorised to interrupt or even abandon a match due to circumstances likely to endanger the players, such as a damp pitch or deterioration of the light.
The wicket-keeper and the batsmen wear protective gear because of the hardness of the ball, which can be delivered at speeds of more than 145 kilometres per hour (90 mph) and presents a major health and safety concern. Protective clothing includes pads (designed to protect the knees and shins), batting gloves or wicket-keeper's gloves for the hands, a safety helmet for the head and a box for male players inside the trousers (to protect the crotch area). Some batsmen wear additional padding inside their shirts and trousers such as thigh pads, arm pads, rib protectors and shoulder pads. The only fielders allowed to wear protective gear are those in positions very close to the batsman (i.e., if they are alongside or in front of him), but they cannot wear gloves or external leg guards.
In 2016, "The Grand Home Season" began for India, including series at home against New Zealand, England, Bangladesh and Australia. India whitewashed New Zealand to regain the number one ranking in Test cricket after almost 10 years. Before the series against England in November 2016, MS Dhoni resigned as captain of India in limited overs, thus handing the captaincy to Virat Kohli across all formats. India beat England across all three formats, with a notable 4–0 win in the Test series. This was followed by Test series wins against Bangladesh and Australia, which meant India reclaimed the Border Gavaskar Trophy. Ravichandran Ashwin became the fastest cricketer of all time to reach 250 wickets; he and Ravindra Jadeja occupied the top two spots in both the ICC Bowlers and All-Rounders rankings at the time. In the process, India became the third team (after South Africa and Australia) to have won their most recent Test series against all the other Test-playing nations. India holds an unbeaten streak of 8 consecutive Test series wins as of 19 August 2017.
Cricket is one of many games in the "club ball" sphere that basically involve hitting a ball with a hand-held implement; others include baseball, golf, hockey, tennis, squash, badminton and table tennis. In cricket's case, a key difference is the existence of a solid target structure, the wicket (originally, it is thought, a "wicket gate" through which sheep were herded), that the batsman must defend. The cricket historian Harry Altham identified three "groups" of "club ball" games: the "hockey group", in which the ball is driven to and fro between two targets (the goals); the "golf group", in which the ball is driven towards an undefended target (the hole); and the "cricket group", in which "the ball is aimed at a mark (the wicket) and driven away from it".
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.