Why is the emission shader clamping even when I increase the strength to crazy high values? I have made a pretty complex scene in Blender 2.82.. I used an HDRi to barely light a scene(strength 0.05).. I just wanted my scene to be lit by street lamps with an emission shaded ball inside the lamp post… Test renders were as expected.. the scene got fully lit by the lamps..
But after I made a few more changes to the scene ( not touching the light sources ).. The scene was dim and dull.. when I increased the strength of brightness to crazy high.. it still did not light up the scene properly..
The scene:

The lamp post array can be seen is made of 3 different meshes: Pole, sphere emitter, covering
Lamp post material:

The pole material

The glass cover material

The actual emission shader
I did not make any changes since I made the test render.. but now, it does not work as intended..
The test render that was qualified:

After the changes:

Just to mention, I did not make any changes to the scale or move or anything.. I literally just appended new meshes for grass to be used as particles in the field present in right side..
The link for the scene:
https://drive.google.com/file/d/1E0inbkPYmTTkzVnRi2sR15HU8w-BSiIj/view?usp=sharing
Edit1: After testing I found out that any value from 1 to 15000K, does not help in lighting up the scene.. it behaves like EEVEE.... the above render was done with 20K strength.. but still not illumination...
Edit2: I tested spot lamps and they do not light up the scene as well..
Expecting Your help..
Mesh lights tend to be pretty noisy, especially if they are small. I hardly ever use only meshlights to illuminate a scene. If you put one of your lights closer to the road, you can see it does not get clamped, it's just very noisy. My suggestion is to switch to spot lights. Your lamp posts are 12m high, so to actually illuminate the street you do need a lot of power. I set the strength of spot to 20,000, that did the trick. If you are uncomfortable with such high numbers you can use a light falloff node to make the lamp ignore the distance.