Have you noticed the order in most yoga studios?  The mats are rolled neatly, the blankets are folded and stacked, the floor is clean.  Perhaps when you enter the room, you perceive a subtle, quiet energy, distinct from the outside world.

You are noticing sauca, which is the first of the 5 niyamas (the second limb of the 8-limbed path of classical yoga.  Here’s a lovely description of these ancient teachings: http://www.yogajournal.com/wisdom/2565).

Sauca can be translated as cleanliness, purity, and the practice of keeping different energies separate.  Hence the meditation at the beginning or end of class, and perhaps the practice of chanting OM.  These are powerful ways to signal the subconscious mind that something profound is taking place.

During your practice, sauca would suggest that you keep your focus inward, allowing a deepening of your own awareness, as distinct from the outward focus of the rest of your day.