For the past few days, the mystery over the leakage of a foul smelling gas has puzzled authorities and residents. The gas strikes only in the evenings and nights and fades as the dawn breaks.

Speculative media reports, apprehensive residents and confused authorities only added to the mystic till pollution control board authorities zeroed on GGCL, a Rs 150-crore company taken over by British Gas last year, holding it responsible for releasing ethyl mercaptan (EM) into air.

There was no less drama when the district collector announced the name of the `culprit' on a local cable network, after breaking open the sealed report submitted by pollution control authorities during a live phone-in programme. ``The suspense is over once and for all,'' he gushed even as thejittery GGCL officials made furtive attempts to raise queries over the phone.

The company which supplies piped natural gas to over 75,000 houses in Surat and over 200 industrial units, after purchasing it from Gas Authority of India Limited (GAIL), flatly denies its involvement. It has questioned the analysis by Gujarat Pollution Control Board and Central Pollution Control Board, saying neither the smell is of EM nor the company the source.

EM, a chemical helps detect leakage, when mixed with the gas, which is odourless. While GGCL, located in Adajan, consumes one barrel of EM every 17 days, Oil and Natural Gas Company, located about 14 kms away at Hazira consumes one every day.

Giants like Reliance, Essar, Kribhco are also located in Hazira, where the needle of suspicion was pointing earlier. Before GGCL was named, every industry worth its salt, from chemical to pesticide and from petrochemical to textile process houses was on the edge and was setting its house in order, lest the smell was traced tothem.

The embarrassed administration had hauled up 12 major units to form a crack team to trace the gas leak. Everytime there was a complaint of gas leak-there were many as telephones in newspaper offices, fire brigade and police control rooms never stopped ringing when people smelt foul, even if that meant gutter line next to their house - the team was to get going, collect samples, analyse them.

This was like asking a gaggle of white-collar employees to turn in a thief among them. But as events proved and GPCB regional officer J B Patel remarked ``they all got busy defending themselves and could neither name the gas nor the source.''

Then CPCB came into picture. This was after local GPCB officials had ended up with a lot of egg on their faces. They were using drager tubes which had long expired. ``EM is a rare parameter, '' was all they could offer by way of an explanation. While GGCL vehemently denies it is responsible for the leak - insiders suggest ``we never keep authorities in good humour unlikeothers '', GPCB is equally emphatic in its assertion. GGCL, located in a low-lying area was under more than seven feet water during the recent floods, but continued to supply gas to its domestic customers.

``That's when the problem started,'' says GPCB. ``GGCL was under flood water even in 1994, '' says the company asking, ``Are we being punished for the good work we did?''

Neither the smell has stopped nor the charges. For all that GGCL is yet to receive notice from GPCB - it did get one for operational deficiency along with Essar on November 21 - while the district collector has threatened to take action under Section 133 of the Criminal Procedure Code for not following board instructions.

So when GGCL officials carry the incense stick on their roof tops they only hope that the wind is not coming from Adajan.