The paper studies Philippine poultry data and revisits the chicken or the egg causality problem to include ducks data. Using quarterly Philippine poultry production time-series from the first quarter of 1980 to the last quarter of 2014, this research finds that chickens came from eggs, which is consistent with the earlier statistical results of Thurman and Fisher (1988), and genetics-based conclusions of Eriksson et al. (2008). However, no conclusive evidence was found using the Philippine duck and duck eggs data. The chicken or the egg conundrum demonstrates the power of Granger causality testing in answering questions of temporal ordering that has various causal applications using macroeconomic, financial, and agricultural time-series data.

It's critical for environmental governance to understand the effectiveness of policy interventions as well as their working mechanisms. This paper focuses on the vehicle license plate-based management, a sort of policy intervention understudied in environmental governance literature. Specifically, we study the automobile purchase restriction (APR), a major method of license management to address urban air pollution and traffic congestion recently launched by the authorities of China. However, limited studies have quantified the environmental impact of such purchase restriction. Based on the panel data of PM2.5 concentration in 330 cities in China during 1998-2016, this study aims to explore the causal impact of Beijing automobile purchase restriction on air quality, using the regression control method and high-dimensional data regression of machine learning. The average PM2.5 concentration did not decrease but increased because of the purchase restriction. Over time, the deterioration effect on urban air quality will not alleviate. Besides, the restriction cannot enhance urban air quality by decreasing the increase of PM2.5. Despite excluding the impact of driving restriction, the purchase restriction markedly aggravate urban air quality. This paper has some policy implications for policymakers on the impact of urban vehicle license management with caution. Hence, it is essential to promote urban economy, production, and lifestyle to attain the win-win goal of air pollution control and urban development.