Bhrigu Express: बलिया की आन बान और शान , भृगु एक्सप्रेस है तुम्हारा नाम। हर रविवार तुमसे मिलना है मेरा काम। - Shanzil Kabir

That we will never get to know. And as you say it is probably a randomly generated list. But without going into the ranking or whether there are other stations dirtier than these 8, I think we may accept that these are not models of cleanliness. So IR would do well to improve them instead of bothering too much about Why ? How ? When ? etc

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