Xiaomi Mi A1 emits the highest level of radiation in a list of current smartphone models, followed by the OnePlus 5T, according to research conducted the German Federal Office for Radiation Protection (Bundesamt für Strahlenschutz). The list of top 16 smartphones emitting the most radiation, compiled by Statista -- based on the data provided by the German body, is majorly dominated by models by Xiaomi and OnePlus, whereas Samsung phones are found to lead the range of least radiation level models. Particularly, the Samsung Galaxy Note 8 and ZTE Axon Elite have emerged as the lowest radiation-emitting phones with a specific absorption rate (SAR) of 0.17 watts per kilogram.
The list published by Statista OnePlus 6T, which is OnePlus' latest flagship, is also amongst the five phones emitting the highest level of radiation with an absorption rate of 1.55 watts per kilogram.
OnePlus 5 that is found to have 1.39 watts per kilogram of specific absorption rate.

Xiaomi Mi A1 is claimed to emit the most radiation
Photo Credit: Statista
Statista has also featured models, including the Samsung model on the list.
In contrast, the list of phones emitting the least radiation compiled by Statista does Moto G5 Plus that emit significantly less radiation.

Samsung Galaxy Note 8 and ZTE Axon Elite are shown emitting least radiation
Photo Credit: Statista
As Martin Armstrong of Statista notes in a post, there isn't any universal guideline for a safe level of phone radiation. However, the German certification for environmental friendliness called 'Der Blaue Engel' (Blue Angel) only certifies models that come with a specific absorption rate of fewer than 0.60 watts per kilogram.
You can take a look at the complete database of phones made by the German Federal Office for Radiation Protection to check the level of radiation your phone emits.
Xiaomi has reached out to Gadgets 360 with a statement regarding the Statista report, and said, "All Xiaomi smartphones sold in India comply with the laws for SAR values and are well under the limit. Mi A1 has a SAR value of 1.26 W/kg (head) and 0.17 W/kg (body) in India. Values shared in the said report have been obtained from tests in (where the conditions and standards for SAR testing and values are different from those in India) and thus cannot be compared to SAR values in India. For reference, India has a maximum limit of 1.6 W/kg while in , the limit is 2.0 W/kg."