. . . . . . . . most popular game is cricket, which is called ". . . . . . . . greatest game in . . . . . . . . world" by . . . . . . . . English.

In the first blank, article "the" will be used because 'most' is a superlative adjective and article "the" is used with superlative adjectives.(concept)
Similarly, in the second blank, 'greatest' is superlative adjective, therefore, article "the" will be used.
In the third blank, article "the" will be used because article "the" is used when there is something only one (the moon, the sun, 'the world').
In the fourth blank, English word is representing a specific group of people. Therefore, article "the" will be used.