Is breathalyzer test reliable if air blank test doesn't show zero reading? Kerala High Court answers

The Kerala High Court recently granted partial relief to a man accused of drunk driving, observing that the breathalyzer test result used on him was invalid since the mandatory air blank test showed a non-zero reading. [Saran Kumar S v. State of Kerala & anr]

Justice VG Arun emphasised that a blank test is taken before the breathalyzer test to verify that the device is functioning correctly and was not influenced by any residual alcohol.

"Therefore, it is mandatory to conduct an Air Blank Test and ensure that the calibration is at 'zero' before taking breath sample using a breath alcohol testing device. This precisely is the reason why, the DGCA made it mandatory to run an Air Blank Test on the instrument and obtain the reading ‘0.000’ before each breathalyzer test," the Court added.

A case was registered against the petitioner Saran Kumar S under Sections 185 (drunken driving) and Sections 181 r/w 3(1) (driving without a valid licence) of the Motor Vehicles Act 1988 (Act) and Section 281 (rash driving or riding in public way) of the Bharatiya Nyaya Sanhita (BNS). He was allegedly driving his scooter dangerously while under the influence of alcohol.

Kumar challenged the charges before the High Court primarily on the ground that the breathalyzer test was conducted improperly, after his arrest rather than immediately upon being stopped. He claimed that he was not medically tested within the stipulated two-hour window under Section 204 of the Motor Vehicles Act.

Most significantly, he pointed out that the breathalyzer air blank test, meant to ensure the device is free of residual alcohol, showed 412 mg/100 ml, thereby questioning the credibility of the 41 mg/100 ml breath test result recorded thereafter.

The prosecution, however, argued that the final report clearly showed that the petitioner was riding in a manner that endangered human life.

The Court, while noting the prosecution's submission, held that the breathalyzer test result could not be relied upon due to the glaring discrepancy in the air blank test, which showed 412 mg/100 ml.

Since no medical test was done within two hours of arrest, there was also no reliable proof that the petitioner had consumed alcohol and thus charge under Section 185 of the Act would not stand.

The Court further found that the petitioner had a valid driving licence at the relevant time, so the charge under Section 181 read with Section 3(1) of the Act could not be maintained.

However, it declined to interfere with the charge under Section 281 of the BNS, noting that whether the petitioner drove in a way that endangered human life would have to be decided during trial.

Accordingly, the Court quashed the final report and further proceedings against the petitioner for offences under Sections 185, 181 r/w 3(1) of the Act.

Noting that the police officers were not aware of the zero reading requirement, the Court also directed the senior public prosecutor to forward a copy of the order to the Director General of Police so that instructions could be issued to all officers to check for a '0.000' reading in the air blank test before using a breathalyzer.

Advocate Faheem Ahsan S appeared for the petitioner.

Senior public prosecutor MC Ashi represented the state.

[Read Order]