Recently, The Economic Times published a story highlighting that the Department of Telecommunications (DoT) has revised the Electromagnetic Field (EMF) exposure limits for telecom service providers in India, increasing the threshold to five times the previous levels. The article speculates that this move could benefit mobile operators by expanding the coverage of their cell sites, potentially reducing the need for additional sites or improving service quality at the cell edges. This, in turn, could lead to better consumer experiences, including improved data speeds and fewer dead zones.
Given that 5G primarily operates in higher frequency bands, such as 3.5 GHz and 26 GHz, the revision is expected to enhance 5G coverage and improve user experience. However, EMF radiation has been a contentious issue since the early days of India’s mobile revolution. Activists have often raised concerns about potential health hazards, taken the matter to court, and campaigned for stricter regulations.
In this article, I aim to simplify and analyze the implications of this new threshold. Does increasing the EMF limits pose greater health risks? Will it provide significant advantages to telecom operators by reducing capital expenditure (capex) or enhancing the quality of mobile services? If so, how? Let’s explore these questions in detail.
What is EMF?
Before delving into these issues, it’s important to first understand EMF (Electromagnetic Waves) from a layman’s perspective. EMF waves travel through free space and are used to transmit information (such as data) from one point to another without relying on physical wires. These “waves” arise from oscillating electric and magnetic fields that are inherently linked, enabling the transfer of energy as they propagate forward.
When EMF waves encounter a human body, the energy they carry (depending on its strength) can potentially interact with cells and tissues, sometimes in harmful ways. This possibility has prompted regulators worldwide to establish strict threshold standards to mitigate any health risks to humans. These limits restrict the strength of RF energy emitted by mobile networks to ensure safety.
However, these safety-imposed limits can compromise a signal’s ability to travel long distances, forcing mobile operators to deploy more cell sites to maintain adequate coverage. This, in turn, increases both their operational costs and capital expenditure requirements.
How Has the Existing Threshold Changed?
The existing limits have been increased fivefold compared to the previous levels. The current thresholds, as outlined in the old notification, are detailed in the table below.
According to the new notification, the threshold limit for power density has been revised to f/400 Watts per square meter for frequencies ranging from 400 MHz to 2000 MHz, and a fixed 5 Watts per square meter for frequencies between 2 GHz and 300 GHz. For example, a base station operating at 700 MHz will now have a permissible power density of 1.75 Watts per square meter (700/400), compared to the earlier limit of 0.35 Watts per square meter. Similarly, for frequencies like 2.3 GHz, 2.5 GHz, or 3.5 GHz, the new limit is 5 Watts per square meter, up from the previous 1 Watt per square meter. This revision significantly increases the permissible emission levels for telecom operators, allowing them to transmit at higher power while adhering to updated safety standards.
How is the Threshold Measured?
The Telecom Engineering Centre (TEC) has developed detailed and technically complex guidelines for measuring EMF thresholds. Simplifying these guidelines, the key principles for these measurements include:
- Worst-Case Scenario: Measurements are conducted considering the worst-case exposure scenario at a given tower location, ensuring that the highest possible EMF levels are accounted for.
- Cumulative Impact: The measurements integrate the combined impact of all base transceiver stations (BTSs) located at the same site. Since RF waves from multiple BTSs, even operating at different frequencies, can overlap and cause the power densities to add up, the cumulative effect is considered critical.
To address these complexities, TEC has developed precise formulas aligned with international standards to evaluate the applicable thresholds at sites hosting multiple BTSs. These guidelines ensure that the total exposure from all sources remains within permissible limits, prioritizing public health while supporting multi-frequency operations at a single location. Measurements are conducted in areas with the highest likelihood of human exposure to RF waves, particularly in the immediate vicinity of the tower, where the overlap of signals could be most significant.
Why Do Different Frequency Ranges Have Different Thresholds?
As shown in the table above, the threshold limits are significantly lower for the lower frequency bands and gradually increase as the frequency rises. Beyond 2 GHz, these thresholds flatten to a constant value up to 300 GHz. The curve below illustrates this trend.
But why is this the case? The explanation lies in the nature of how electromagnetic waves behave at different frequencies. Lower frequency bands travel farther, bend around corners, and penetrate human skin more deeply compared to higher frequency bands. In contrast, higher frequency waves, such as those above 2 GHz, are highly directional, easily obstructed by barriers, and have limited penetration indoors.
As a result, the threshold levels are stricter at the lower end of the spectrum to mitigate potential risks associated with deeper penetration. These limits are relaxed for higher frequencies, where the waves are less intrusive and pose fewer risks to human health.
Will the New Threshold Increase Health Risks and Help Operators Save Capex?
This is perhaps the most critical question for readers. Beyond health concerns, the primary goal of revising these thresholds is to provide operators with the flexibility to increase the power of their BTSs (Base Transceiver Stations), thereby extending the coverage of cell sites and improving the user experience. Let’s delve deeper into both aspects to provide clarity, considering the constraints within which we operate.
Health Risks:
The new limits set by the DoT remain well below the ICNIRP (International Commission on Non-Ionizing Radiation Protection) standards—approximately half of the permissible international threshold. This places India’s revised standards far from the so-called “danger zone” as defined by global safety benchmarks. Moreover, the worst-case criteria are applied when measuring compliance. In a tower hosting multiple BTSs across various frequency bands, the overall threshold is dictated by the BTS operating at the lowest frequency. This is because lower frequencies penetrate deeper into human tissue, posing a higher potential risk. Consequently, even if higher-frequency BTSs are allowed increased thresholds, their power levels remain constrained by the lower-frequency BTS (e.g., 700 MHz), whose threshold has been increased from 0.35 W/m² to 1.75 W/m². As a result, the relaxation provides limited incremental coverage, primarily governed by the 700 MHz band.
Capex Savings:
Whether the relaxed thresholds will translate into capital expenditure (capex) savings depends on the type of site—coverage site or capacity site:
- Coverage Sites:
At coverage-focused sites, increasing BTS power under the new limits could theoretically extend the coverage area and improve downlink performance (e.g., better speeds at the network edge). However, uplink performance remains unchanged, as it is constrained by the handset’s transmit power and the unaltered SAR (Specific Absorption Rate) configuration of mobile devices. This asymmetry between uplink and downlink could limit the overall benefits. - Capacity Sites:
For capacity-focused sites, increasing BTS power to align with the new regulations is unlikely to be beneficial. Higher power levels can lead to increased interference with neighboring sites, ultimately reducing the overall network capacity. In such scenarios, the risks of interference outweigh any potential coverage or performance gains, making the new thresholds less impactful.
Therefore, while the relaxed EMF thresholds might provide marginal gains in extending coverage at coverage sites, these gains will primarily be limited to the downlink. The uplink will remain constrained, leading to increased asymmetry in the network. Additionally, at capacity sites, the risk of increased interference could negate any benefits, making capex savings minimal or non-existent. Overall, the practical advantages of the revised thresholds appear to be modest at best.
DoT’s Audit – Measured Values vs Threshold
The best way to evaluate the impact of the new EMF threshold relaxation is by analyzing data from the DoT’s latest audit report for the financial year 2024-25, which captures measured EMF values at site locations and compares them to the prescribed thresholds under the current rules (before the new notification). The chart below illustrates the results of these audits, conducted either by DoT independently or in response to public requests.
The dashboard is divided into two sections:
- Left Section: Captures DoT’s prescribed limits for all states. It maps the number of sites audited in each state against threshold bins defined in increments of 0.02 Watts/Sq. Meter. This provides a clear distribution of sites aligned to the prescribed limits.
- Right Section: Captures the actual measured values across the same states. Here, bins are defined in increments of 0.01 Watts/Sq. Meter, allowing a detailed view of how many sites fall into specific measured ranges.
From the data, it is evident that only 52 sites on a pan-India basis have measured values falling under the stricter threshold of 1 Watt/Sq. Meter, and only 1 site has crossed the 0.2 Watt/Sq. Meter mark. Remarkably, 97% of all audited sites register measured values of 0.04 Watts/Sq. Meter or lower, which is merely 11% of the current maximum threshold limit (0.04/0.35).
This clearly demonstrates that the existing network is operating well below the threshold limits set by DoT, even under the stricter old standards. These findings indicate significant headroom in compliance, supporting the argument that the current network is already operating safely and within regulatory guidelines.
Conclusion
The analysis clearly demonstrates that the increased EMF power level thresholds pose minimal health risks, as current operations already comply with standards that are 10 times stricter than ICNIRP guidelines. Even with the relaxation to twice the existing levels, the incremental health risk is negligible. This is supported by the fact that most measured sites operate well below the prescribed limits, ensuring significant safety margins.
From a coverage and cost perspective, the benefits are likely to be marginal. Capacity-focused sites are unlikely to reap advantages, as increasing power levels could lead to significant interference with neighboring sites, ultimately degrading network performance. Coverage-focused sites may see some improvements in extending cell coverage and enhancing downlink performance (e.g., better speeds at network edges). However, these gains will remain constrained by the “worst-case principle”, where the overall power levels of all BTSs in a tower are dictated by the lowest frequency deployed, such as 700 MHz. Furthermore, the uplink performance will remain limited by handset power and SAR configurations, leading to increased asymmetry between uplink and downlink speeds.
Given these constraints, the relaxed thresholds seem to have minimal immediate impact. Operators will need to undertake significant reconfiguration and optimization efforts to prevent interference between neighboring sites, a challenging and time-consuming process that could impact network stability. While there may be some benefits in isolated single-BTS coverage sites, especially in scenarios where millimeter wave bands like 26 GHz are deployed, the broader network of multi-BTS towers is likely to function as before.
In conclusion, while the relaxed thresholds provide flexibility, their impact on consumers and network performance will depend on how operators leverage this change. At present, the benefits appear modest, with minimal risks to public health and limited improvements in network coverage or operational efficiency.
