DID YOU KNOW THAT THERE IS A MINIMUM LIGHTING ILLUMINATION REQUIREMENTS ACCORDING TO LAW?
IN THE ONTARIO BUILDING CODE | LIGHTING
Code 3.16.1.5.
- Walkways and platforms shall be equipped to provide illumination to an average level not less than 50 lx at floor or tread level and at angles and intersections at changes of level where there are stairs or ramps.
But what this means?
The lux (symbol: lx) is the si unit of illuminance measuring luminous flux per unit area. It is equal to one lumen per square metre . One lux is equal to one lumen per square meter:
Illuminance is a measure of how much luminous flux is spread over a given area. One can think of luminous flux (measured in lumens) as a measure of the total “amount” of visible light present, and the illuminance as a measure of the intensity of illumination on a surface. A given amount of light will illuminate a surface more dimly if it is spread over a larger area, so illuminance is inversely proportional to area when the luminous flux is held constant.
The lux is one lumen per square metre (lm/m2), and the corresponding radiometric unit, which measures irradiance, is the watt per square metre (W/m2). There is no single conversion factor between lux and W/m2; there is a different conversion factor for every wavelength, and it is not possible to make a conversion unless one knows the spectral composition of the light.
The peak of the luminosity function is at 555 nm(green); the eye’s image-forming visual system is more sensitive to light of this wavelength than any other
Earlier it was common with light levels in the range 100 – 300 lux for normal activities. Today the light level is more common in the range 500 – 1000 lux – depending on activity. For precision and detailed works, the light level may even approach 1500 – 2000 lux.
Here are some examples of LUX:

So the level of light provided will be measured by inspectors by lux meter to see if the illumination meet the code and will ask
Additional lighting equipment is often necessary to compensate the low levels.
Earlier it was common with light levels in the range 100 – 300 lux for normal activities. Today the light level is more common in the range 500 – 1000 lux – depending on activity. For precision and detailed works, the light level may even approach 1500 – 2000 lux
Generally, factors that affect the effectiveness of illumination are quantity and quality of light, amount of flicker, amount of glare, contrast and shadows. Each factor must be adjusted differently to optimize illumination in emergency, safety, operations, and security situations, for instance. Lighting Standards also serve to address the plethora of other concerns associated with the design, placement, installation, and minimum energy requirements and efficient allocation of illumination in different locations with different purposes, as well as the efficiency, durability, cost, and maintainability.
Additional Recommended Light Levels Indoors :

Wishing this unrefined description of lux will help you have a sense of LUX and illumination
This was a plain abstraction from waves and modern physics taken by students of engineering science division faculty of applied science and engineering.