A division bench comprising Justices Anil Dev Singh and Mukul Mudgal issued the notices to the Ministries of Environement, Forests, and Defence, besides the Central Pollution Control Board (CPCB), Central Public Works Department (CPWD), the Delhi Government's PWD, Delhi Development Authority and the Delhi Jal Board.

Asking the respondents to reply to the points raised in the public interest litigation by judicial activist B L Wadhera, the court directed that some senior officials from these departments be present in court on October 26, the next date of hearing.

The petitioner said fly-ash disposed of in various dumping grounds in the city was being blown away, causing health hazards in neighbouring areas.

He said if the government formulated a proper plan for fly-ashmanagement, it could prove to be a boon because of its multi-purpose utility.

The director of the fly-ash mission in the Department of Science and Technology said in court that laboratory tests have proved beyond doubt the multi-purpose use of the material.

He submitted that fly-ash could be used for making bricks, concrete blocks, embankments and filling roads, and as a substitute for cement for upto 30 per cent in construction works.

The most effective use could be as fertiliser, as up to 15 percent of its mixture in a farm increases the fertility of land many-fold, he claimed.

Wadhera informed the court that Army, Navy and Air Force chiefs, in their reply to his letters, had expressed their willingness to use fly-ash for various purposes in cantonments.

Meanwhile, the DDA said, in its affidavit, that fly-ash bricks could not be used in building construction on account of many factors, including higher cost. ``So far, the attempt made to produce fly-ash bricks and tiles by different agencies havenot been satisfactory,'' it said.

Since the fly-ash bricks were only at a developmental stage, these could not be used for construction till their durability was established beyond doubt, the affidavit added.