Sky appears blue at mid-day. Is Tyndall effect seen here?

Yes. Tyndall effect is seen when the sky appears blue in the mid-day. When the light scatters by dust particles and air molecules, the waves having lower frequency get scattered while the waves having higher frequency get passed through by diffraction. Due to all this the voilet spectrum of sunlight becomes visible and we know that voilet light is very less that makes the sky to appear blue.