Why do your eyes feel dazzled when bright sunlight is reflected from buildings or roads?

looking at the Taj Mahal at noon time. Your eyes will feel completely dazzled. Glare of reflected sunlight is quite unbearable. The light intensity is so high that one 's eyes can even start watering.

Why does it happen?

The reason lies in polarization of light. Any light, especially sunlight, is made up of rotating electric and magnetic fields. These field directions at any point of time are randomly directed. When sunlight is reflected from certain surfaces, such as white Taj Mahal or buildings, the electric field can acquire just one direction, generally direction parallel to the surface that is reflecting the light.. This is known as polarization of light. When such a polarized light reaches your eyes, the light intensity experienced is very high. This is why we feel dazzled or feel the glare of sunlight.

Why is advisable to wear polarized sun glasses while driving on roads during daylight?

The way to avoid this glare is to change your direction of viewing the surfaces, so that the polarized light is avoided. This is generally not possible, therefore the drivers wear polarizing sunglasses. A polarizing sunglass is made up of material that blocks light having certain electric field directions and allows unpolarized light to pass through.