It is closely related to Vasantha, as the two share many characteristic prayogas and have similar scales.
[1] Lalitha is often used In Tamil film songs, especially by Ilayaraja who has composed five film songs based on this ragam.
It is called a shadava raga structure is as follows (see swaras in Carnatic music for details on below notation and terms): This scale uses the notes shadjam, shuddha rishabham, antara gandharam, shuddha madhyamam, shuddha dhaivatham and kakali nishadam.
Lalitha has ample scope for alapana.
This scale has been used by many composers for compositions in classical music.