Notification no. 24/2004 ST dated 10-9-2004 as amended vide notification no. 3/2010 ST dated 27-2-2010 provides exemption from service tax in relation to vocational training provided by a vocational training institute.

For this purpose, vocational training means, an Industrial Training Institute or an Industrial Training Centre affiliated to the National Council for Vocational Training, offering courses in designated trades as notified under the Apprentices Act, 1961(52 of 1961)]

The list of designated trades can be downloaded from here

Exemption from service tax for vocational training institutes offering designated trades under notified apprenticeship rules. Exemption from service tax applies to vocational training provided by Industrial Training Institutes or Industrial Training Centres affiliated to the National Council for Vocational Training when those institutes offer courses in designated trades notified under the Apprentices Act, 1961; eligibility depends on conformity with Schedule I entries specifying trade, apprenticeship period, apprentice to worker ratio, training duration and educational qualifications.