A new report released by NYC-based GroupM – a global media investment management op and parent co to WPP agencies like Maxus, MediaCom, Mediaedge:cia and MindShare – predicts a 20% increase in ad spending in India across most media platforms this year, to $5.6 billion. It also predicts a 19% increase next year to $6.6 billion, making it the world’s 15th-largest advertising market – up 11 spots from its 2000 ranking of 26th. The report, This Year, Next Year: India Media Forecasts, is part of an annual media and marketing forecasting series.

Most of the ad spend growth has been attributed to traditional media. The report indicates that ad spending in online media, where penetration has been slow, has been on the decrease. In 2007, online usage was at 46 million monthly – accounting for only 4% of the country’s population. This year, GroupM expects Internet ad spending to account for only 2.6% of the country’s measured ad investment.

‘India is set to deliver sustained long-term advertising growth,’ says London-based GroupM futures director Adam Smith. ‘It is also one of the world’s most under-advertised countries.’ Smith adds that measured advertising investment is half of the global norm of around 1% GDP.

A copy of the full This year next Year: India 2008 report is available here.