Section 425,426 and 427 are all related to mischief and they all exist.Mischef is an offence related to damage of property.The difference between these sections are that in section 425 defines the offence of mischief —Whoever with intent to cause, or knowing that he is likely to cause, wrongful loss or damage to the public or to any person, causes the destruction of any property, or any such change in any property or in the situation thereof as destroys or diminishes its value or utility, or affects it injuriously, commits “mischief”. Section 426 provides the punishment for the above offence(425) and therefore prople are accused of mischief under section 425 and convicted under section 426. Section 427 is an aggrevate form of mischief and carry a more strict punishment with inprisonment upto 2 years or fine.
Section 427-440 comes under aggravated forms of mischief, in cases like -
(1) commiting mischief and therby causing damage amounting to Rs 50 or more
(2)mischief by killing poisioning,maiming or rendering useless,elephant,camel,horse,mule,buffalo,bull,cow or ox or any other animal of value of more than Rs 50
(3)mischief by injury to works of irrigation,etc
Hope this helps