The advertisement industry is expecting a 15-20% increase in festive ad spending due to the new goods and services tax regime starting on September 22. This will add Rs 10,000 crore to the total of Rs 60,000 crore during the 100-day festival period. The government and its agencies will spend Rs 1,500-2,000 crore to educate consumers about product price cuts, with a focus on digital platforms.