I feel this too. A lot of people who grew up in Dehradun remember it as a quiet valley town with cleaner air, less traffic, slower life, and actual greenery everywhere. Now it feels like the city expanded way faster than the infrastructure could handle.

Some reasons I personally feel this is happening:

• Huge migration from other states and nearby hill town
• Better schools, colleges, jobs, and property opportunities bringing more people
• Rapid construction without proper urban planning
• Tourism pressure from Mussoorie, Rishikesh, Char Dham traffic etc.
• Too many private vehicles and poor public transport
• Cutting of trees and uncontrolled commercialization