Most dirty trains in all zones,please do not mind its my personal experience and train dirty does not mean all trains of that zone are dirty.
CR- sorry its Janeshwari Delux only for me till now.
NWR- Marudhar
NCR- Agra delhi Intercity.
ER-...
more... Howrah Jodhpur
NR- Simanchal...
Absolutely among these trains no train stand even near by Seemanchal Express so due to grace of Simanchal my vote goes to NR only.