These are Refinery products, Electricity, Steel, Coal, Crude oil, Natural gas, Cement and Fertilisers.
The first official attempt to compute the IIP was made much earlier than even the recommendations on the subject at the international level.
With the inception of the Central Statistical Organization in 1951, the responsibility for compilation and publication of IIP was vested with this office.
The items in this index were classified according to the International Standard Industrial Classification (ISIC) 1948 of all economic activities.
However, the mineral index prepared by the IBM excluded gold, salt, petroleum and natural gas.
The working group (set up in 1978) under the Chairmanship of the then Director General of CSO, decided to shift the base to 1980–81, to reflect the changes that had taken place in the industrial structure and to accommodate the items from small-scale sector.
A notable feature of the revised 1980 index number series was the inclusion of 18 items from the SSI sector, for which the office of the Development Commissioner of Small-Scale Industries (DCSSI) could ensure regular supply of data.
For the period April 1981 to June 1984 in respect of these 18 items, average base year (1980–81) production as obtained from DGTD was used.
The next revision of IIP with 1993–94 as the base year containing 543 items (with the addition of 3 items for mining sector and 188 for the manufacturing sector) has come into existence on 27 May 1998 and ever since, the quick estimates of IIP are being released as per the norms set out for the IMF’s SDDS2, with a time lag of six weeks from the reference month.
As per chief statistician T C A Anant, this index shall give a better picture of growth in various sectors of the economy, because it is broader and includes technologically advanced goods such as cell phones and iPods.
The previous base year (1993–94) was not usable as the list contained an array of outdated items such as typewriters and tape recorders.